Vulcanized rubber molded product, method of producing the same, and use of the molded product

ABSTRACT

The present invention provides a vulcanized foamed rubber molded product which has surface smoothness equal to or higher than that of a non-foamed vulcanized rubber molded product, has excellent mechanical strength properties, compression set resistance and abrasion resistance and a non-foamed vulcanized rubber molded product which is superior in surface smoothness to a conventional non-foamed vulcanized rubber molded product and has excellent compression set resistance, mechanical strength properties and abrasion resistance, as well as a method of producing the same. The molded product of the present invention is characterized in that the amount of sulfur atoms present in the surface thereof is at least 1.2 times as high as the amount of sulfur atoms present in a cut face obtained by cutting the surface to a depth of 1.0 mm in the vertical direction. The method of producing comprises allowing droplets or spray of a liquid containing an elementary substance consisting of a non-oxygen element in the group VI in the periodic table to adhere to the surface of a non-vulcanized rubber composition containing an elemental sulfur and/or a sulfur compound as a crosslinking agent, and then vulcanizing or vulcanizing and foaming the composition.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a vulcanized rubber molded productobtained by sulfur crosslinkage (vulcanization) and a method ofproducing the same and in particular to a vulcanized rubber moldedproduct that is a foamed product obtained by continuously crosslinking(vulcanization)/foaming a rubber composition containingethylene/α-olefin/non-conjugated polyene copolymer rubber etc. by avulcanizing device such as a heated air vulcanizing bath (HAV), anultra-high frequency vulcanizing device (UHF) etc., which is excellentin design, excellent in properties such as mechanical strengthproperties (tensile strength at break, tensile elongation at break),compression set resistance, abrasion resistance etc., and suitable forapplications to automobile weather strips, glass run channels, openingtrims, hoses etc., and a method of producing the same.

2. Description of the Related Art

Ethylene/α-olefin/non-conjugated polyene copolymer rubber such asethylene/propylene/diene copolymer (EPDM) etc. is generally excellent inweatherability, heat resistance and ozone resistance, and is used forexample in applications to automobiles, specifically vulcanized rubberproducts such as glass run channel products, window frame products orhose products.

The glass run channel products and window frame products are used forthe purpose of protection against rain, wind and sound, and areimportant sealing parts. For increasing the duration of automobiles andfor making maintenance free, there is a need for further improvements insealing performance and long-term duration of the sealing performance.In respect of the hose products, there is a need for furtherimprovements in heat resistance and sealing performance.

These properties are required as functions of the products, but thedesign of the vulcanized rubber products is also important. In thepresent specification, the “design” of the vulcanized rubber productsrefers to design depending on the surface smoothness, shape retentionstability etc. of mainly the vulcanized rubber molded products (foamedproducts, non-foamed products).

The weather strip products are seen upon getting into or getting off anautomobile, and thus their design exerts a significant influence on theimage of the automobile itself.

When the vulcanized rubber product is a foamed product, its design isrelated closely to the state of foamed cells. When the foamed cells pushup the surface of the vulcanized rubber product, the surface of theproduct becomes uneven to deteriorate its design. On the other hand, avulcanized rubber product having the cells in broken state is notpreferable because water permeates through the surface to deterioratethe functions thereof as a sealing product.

As a method of solving these problems, a method which involves surfacetreatment of a vulcanizable molded product (non-vulcanized rubber)consisting of ethylene/α-olefin copolymer rubber by coating the surfaceof the molded product with a treatment liquid containing a xanthogenatefor accelerating vulcanization reaction and then vulcanizing thenon-vulcanized rubber to give a vulcanized rubber molded product(non-foamed product) and a method which involves surface treatment of avulcanizable, foaming molded product (non-vulcanized, non-foamed rubber)consisting of ethylene/α-olefin copolymer rubber by coating the surfaceof the molded product with the above treatment liquid and thenvulcanizing and foaming the non-vulcanized, non-foamed rubber to give avulcanized rubber molded product (foamed product) are disclosed in JP-ANo. 4-202237 (page 2, upper right column to page 3, upper left column,and page 7, upper right column).

The vulcanized rubber molded product obtained by this conventionalsurface treatment method is excellent in design, but the chemical odorof the xanthogenate is strong, and it is troublesome to remove thechemical odor. As the method of coating the surface of thenon-vulcanized rubber with the above treatment liquid, a dipping methodusing a coating bath is presented, but in this method where thenon-vulcanized rubber is passed through the coating bath, the rubbersurface is marred or the rubber molded product is deformed, and therubber molded product in such state is converted into a vulcanizedrubber product, which may result in deterioration of the design of theproduct. When the non-vulcanized rubber is molded at a lower moldingspeed, the rubber moves in a zigzag direction in a vulcanizing bath andentangled or bent in the chamber, which may result in problems such asfailure to give an excellent vulcanized rubber product.

When the automobile weather strip product is divided roughly dependingon the site where it is used, the weather strip has 3 constitutions,that is, one layer consisting of sponge rubber, two layers of spongerubber/solid rubber, and three layers of sponge rubber/solidrubber/metal. The “sponge” refers to a foamed product, while the “solid”means a non-foamed product. The foamed product includes a product calledslightly foamed solid.

The sponge rubber and solid rubber in these constitutions are differentfrom each other in respect of performance required thereof, and are thusgenerally often different from each other in respect of the compositionof starting materials. Accordingly, the sponge rubber and solid rubbershow a different rate of crosslinkage at the molding temperature used,and thus one rubber tends to be excessively crosslinked while the otherrubber tends to be poorly crosslinked. As a result, the productconsisting of the 2 or 3 layers described above can be poor ininterfacial adhesion between the sponge rubber and solid rubber, toeasily cause defects such as interfacial separation.

For the sponge rubber in such a state as to give a sponge product byvulcanization reaction accompanied by foaming reaction, the time inwhich the maximum vulcanization reaction is generally reached is almostidentical with the time in which the maximum foaming reaction isreached. When this balance is lost or the vulcanization reactionproceeds at a relatively higher rate than the foaming reaction, thesurface smoothness of the sponge rubber product is improved and thedesign of the product is improved. However, such materials may scorchduring molding to fail to give a product and are thus not practical.

Conventionally, when vulcanized rubber products having extremelyexcellent surface smoothness are to be obtained, many problems describedabove occur, and thus vulcanized rubber molded products (e.g. extrudedsponge rubber, extruded solid rubber) having excellent surfacesmoothness have not been obtained.

Excellent mechanical strength properties and abrasion resistance arerequired of weather strip products and hose products. The weather stripproducts are desired to be resistant to abrasion with an automobile doorand glass and resistant to abrasion with clothes in getting into orgetting off an automobile. The hose products are required to beabrasion-resistant in order to prevent damage caused by abrasion amongthe hoses or between the hose and other products. It is known thatresistance to such abrasion, or abrasion resistance, can be improved byincreasing the density of crosslinkage by blending larger amounts of acrosslinking agent (vulcanizing agent), a vulcanizing accelerator and acrosslinking assistant. However, the tensile elongation and tensilestrength have the optimum value respectively, and when tensileelongation is determined to be increased by the composition of startingmaterials, tensile strength is decreased, while when tensile strength isdetermined to be higher, tensile elongation is decreased. Accordingly,the design of rubber compositions achieving both tensile elongation andtensile strength is extremely difficult.

Under such circumstances, there is a need for a vulcanized rubber moldedproduct which is a foamed product (sponge), has surface smoothness equalto or higher than that of a non-foamed product (solid) as a vulcanizedrubber molded product, has excellent mechanical strength properties(tensile strength at break, tensile elongation at break etc.), and hascompression set resistance and abrasion resistance as well as a methodof producing the same, and there is also need for a vulcanized rubbermolded product which is a non-foamed product (solid), is superior insurface smoothness to a conventional non-foamed vulcanized rubber moldedproduct and has excellent compression set resistance, mechanicalstrength properties (tensile strength at break, tensile elongation atbreak etc.) and abrasion resistance as well as a method of producing thesame.

SUMMARY OF THE INVENTION

The present invention is to solve the problems in the above prior art,and the object of the present invention is to provide a vulcanizedrubber molded product which is a foamed product (sponge), has surfacesmoothness equal to or higher than that of a non-foamed product as avulcanized rubber molded product, has excellent mechanical strengthproperties (tensile strength at break, tensile elongation at breaketc.), and has compression set resistance and abrasion resistance and amethod of producing the same, as well as a vulcanized rubber moldedproduct which is a non-foamed product (solid), is superior in surfacesmoothness to a conventional non-foamed vulcanized rubber molded productand has excellent compression set resistance, mechanical strengthproperties (tensile strength at break, tensile elongation at break etc.)and abrasion resistance and a method of producing the same.

The vulcanized rubber molded product according to the present inventionis characterized in that the amount of sulfur atoms present in thesurface of the vulcanized rubber molded product is at least 1.2 times ashigh as the amount of sulfur atoms present in a cut face obtained bycutting the surface to a depth of 1.0 mm in the vertical direction.

The vulcanized rubber molded product may be a foamed product or anon-foamed product.

In the vulcanized rubber molded product according to the presentinvention, it is preferable that the vulcanized rubber molded producthas a hollow part at least partially, and meets the followingrelationship:A/B<1.0wherein A is the surface roughness (RzD) of the vulcanized rubber moldedproduct, and B is the roughness (RzD) of the internal surface of thehollow.

The method of producing a vulcanized rubber molded product according tothe present invention comprises allowing droplets or spray of a liquidcontaining an elementary substance consisting of a non-oxygen element inthe group VI in the periodic table to adhere to the surface of anon-vulcanized rubber composition containing an elemental sulfur and/ora sulfur compound as a crosslinking agent, and then vulcanizing orvulcanizing and foaming the composition.

In the method of producing a vulcanized rubber molded product accordingto the present invention, the non-vulcanized rubber composition isshaped into a predetermined product shape, and then the droplets orspray can be allowed to adhere to the surface of the composition.

Preferably, the rubber contained in the non-vulcanized rubbercomposition is an ethylene/α-olefin/non-conjugated polyene copolymer.

In one embodiment of the method of producing a vulcanized rubber moldedproduct according to the present invention, when a non-vulcanized rubbercomposition containing, for example, an elemental sulfur and/or a sulfurcompound (so-called a vulcanizing agent) as a crosslinking agent andethylene/α-olefin/non-conjugated polyene copolymer rubber as a rubber isextruded and shaped in a predetermine product shape via an extruder andcontinuously crosslinked or crosslinked and foamed, the surface of thenon-vulcanized rubber composition having a predetermined product shape,while being discharged from the extruder and reaching a vulcanizingbath, is allowed to have droplets or spray of a liquid containing anelementary substance consisting of a non-oxygen element in the group VIin the periodic table.

In the present invention, the liquid is preferably sprayed to generatedroplets or spray and allowed to adhere to the surface of thenon-vulcanized rubber composition.

The liquid is preferably a dispersion of an elementary substanceconsisting of a non-oxygen element in the group VI in the periodictable.

The vulcanized rubber molded product of the present invention or thevulcanized rubber molded product obtained by the method of producing ofthe present invention is preferably extruded sponge rubber or extrudedsolid rubber.

The vulcanized rubber molded product of the present invention or thevulcanized rubber molded product obtained by the method of producing ofthe present invention is used preferably in any application selectedfrom the group consisting of a weather strip, a glass run channel, anopening trim and a hose.

The vulcanized rubber molded product according to the present inventionis a foamed product (sponge) or a non-foamed product (solid) wherein theamount of sulfur atoms present in the surface thereof is at least 1.2times as high as the amount of sulfur atoms present in a cut faceobtained by cutting the surface to a depth of 1.0 mm in the verticaldirection, and thus the foamed product in the vulcanized rubber moldedproducts of the present invention has surface smoothness equal to orhigher than that of a non-foamed product as a vulcanized rubber moldedproduct, has excellent mechanical strength properties (tensile strengthat break, tensile elongation at break etc.), and has compression setresistance and abrasion resistance. In the vulcanized rubber moldedproducts of the present invention, the non-foamed product is superior insurface smoothness to a conventional non-foamed vulcanized rubber moldedproduct and has excellent compression set resistance, mechanicalstrength properties (tensile strength at break, tensile elongation atbreak etc.) and abrasion resistance.

According to the method of producing the vulcanized rubber moldedproduct in the present invention, droplets or spray of a liquidcontaining an elementary substance consisting of a non-oxygen element inthe group VI in the periodic table are allowed to adhere to the surfaceof a non-vulcanized rubber composition containing an elemental sulfurand/or a sulfur compound as a crosslinking agent, followed byvulcanizing or vulcanizing and foaming the composition, and thus thevulcanized rubber molded product (foamed product, non-foamed product) ofthe invention having the above effects can be obtained.

By the surface treatment method of spraying the above liquid onto thesurface of the non-vulcanized (non-foamed) rubber composition beforevulcanization of sulfur and/or sulfur compound according to the presentinvention, the design of the resulting rubber product can besignificantly improved, and particularly the foamed product can achieveexcellent design which has hardly been achieved in the prior art andsimultaneously achieve excellent compression set resistance and shaperetention with improvements of foaming efficiency, and is also excellentin mechanical strength (tensile strength at break) and tensileelongation at break. The solid product is also excellent in compressionset resistance, shape retention, mechanical strength (tensile strengthat break), and tensile elongation at break.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic plan of a tubular sponge rubber for explaining amethod of measuring shape retention.

FIG. 2 is a schematic view of a continuous extrusion line used in theExamples in the present invention.

FIG. 3 is a schematic view showing one example of a cut face formeasuring the amount of sulfur atoms present in a cut face obtained bycutting the surface of a molded product to a depth of 1.0 mm.

FIG. 4 is a schematic view showing another continuous vulcanizingmolding device equipped with one example of a spraying device.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, the vulcanized rubber molded product according to thepresent invention and the method of producing the same are described inmore detail.

As described above, the vulcanized rubber molded product of the presentinvention is a foamed product (sponge) or a non-foamed product (solid)wherein the amount of sulfur atoms present in the surface thereof is atleast 1.2 times, usually 1.2 to 10 times, preferably 1.2 to 5 times,more preferably 1.8 to 3 times, as high as the amount of sulfur atomspresent in a cut face obtained by cutting the surface to a depth of 1.0mm in the vertical direction. The vulcanized rubber molded productaccording to the present invention can attain the above ratio of presentsulfur atoms, for example by using a single rubber composition asdescribed above without using a product consisting of two or more moldedproducts laminated therein. This means that the vulcanized rubber moldedproduct of the present invention has a structure of higher density ofcrosslinkage in the surface than in the inside. When the amount ofsulfur atoms present in the surface of the vulcanized rubber moldedproduct is at least 1.2 times as high as the amount of sulfur atomspresent in the cut face, excellent design, excellent mechanical strengthproperties (tensile strength at break, tensile elongation at break) andabrasion resistance can be simultaneously achieved. The amount of sulfuratoms is more preferably up to 10 times in order to prevent sulfur frombeing precipitated in the surface of the molded product. The vulcanizedrubber molded product wherein the amount of sulfur atoms present in thesurface of the molded product is regulated in the above range improvesmechanical strength properties, abrasion resistance, and compression setresistance. As a matter of fact, there is no particular limitation withrespect to attachment of the molded product of the present invention toanother molded product.

The method of quantifying the amount of sulfur atoms will be describedin the Examples. For preparation of a cut face by cutting the surface ofthe molded product to a depth of 1.0 mm to measure the amount of sulfuratoms present in the cut face, the surface of the molded product may becut to a depth of 1.0 mm in the direction of vertical depth from thesurface. Specifically, a cut face having a size of 1 cm² or more (forexample at least 10 mm×at least 10 mm) is formed by cutting to a depthof 1.0 mm from the surface in the vertical direction. The depth of thecut face may be 1.0 mm or more in practice, for example 1.0 mm or more,and is specifically allowable up to about 1.3 mm. It is howeverpreferable that the cut face does not penetrate from the surface via themolded product to the other side. When not only the surface includingthe cut face penetrating the molded product but also the other side istreated with the specific liquid by the method of the present invention,the concentration of sulfur shall be measured in a position excluding aregion of higher sulfur concentration in the vicinity of the other side.

In this case, the cut face may be formed such that the minimum distancebetween the cut face and the other side is 0.5 mm or more.

Even if the cut face is not surfaced, measurement is not particularlyinfluenced.

FIG. 3 shows a cut face for measuring the amount of sulfur atoms presentin the inside of a molded product such as a hollow extrusion moldedproduct.

The sulfur content in the surface of the molded product is measured, andthen a surface layer of 1.0 mm in thickness from the surface of themolded product is uniformly cut and then the sulfur content in the newsurface may be measured. When the side opposite to the surface via themolded product is also treated with the specific liquid by the method ofthe present invention, the portion to be measured shall have a thicknessof 0.5 mm or more from the surface of the opposite side.

The vulcanized rubber molded product of the present invention describedabove makes use of a rubber composition containing a elemental sulfurand/or a sulfur compound as a crosslinking agent (a non-vulcanizedrubber composition or a non-vulcanized non-foamed rubber composition),as well as a liquid containing an elementary substance consisting of anon-oxygen element in the group VI in the periodic table (hereinafter,also referred to as the “treatment liquid”) in producing. As describedlater, the vulcanized rubber molded product can be produced by allowingdroplets or spray of the liquid to adhere to the surface of thevulcanized rubber composition and then vulcanizing or vulcanizing andfoaming the composition.

Rubber Composition

The rubber composition used in the present invention contains at leastrubber and a crosslinking agent (vulcanizing agent).

[Rubber]

The rubber used in the present invention includes, for example,conventionally known ethylene/α-olefin copolymer rubber andethylene/α-olefin/non-conjugated polyene copolymer rubber. Theethylene/α-olefin copolymer rubber includes, for example, anethylene/propylene random copolymer (EPR) etc. Theethylene/α-olefin/non-conjugated polyene copolymer rubber includes, forexample, ethylene/propylene/diene copolymer rubber (EPDM) etc.

The rubber used in the present invention can be used by blending knownother rubber with the ethylene/α-olefin copolymer rubber and/orethylene/α-olefin/non-conjugated polyene copolymer rubber in such arange that the object of the present invention is not hindered. Theother rubber includes, for example, isoprene-based rubber such asnatural rubber (NR) and isoprene rubber (IR), conjugated diene-basedrubber such as butadiene rubber (BR), styrene/butadiene rubber (SBR),acrylonitrile/butadiene rubber (NBR) and chloroprene rubber (CR), andbutyl rubber (IIR).

In particular, the ethylene/α-olefin/non-conjugated polyene copolymerrubber is preferable. This copolymer rubber may be blended with theethylene/α-olefin copolymer rubber and/or various kinds of the abovediene-based rubber.

The ethylene/α-olefin/non-conjugated polyene copolymer rubber used inthe present invention is preferably ethylene/α-olefin/non-conjugatedpolyene copolymer rubber having the following properties (i) to (iii)[referred to hereinafter as “ethylene/α-olefin/non-conjugated polyenecopolymer rubber (A)”] obtained by random copolymerization of ethylene,C3 to C20 α-olefin and non-conjugated polyene.

(i) Molar Ratio of Ethylene to C3 to C20 α-Olefin (Ethylene/α-Olefin)

The molar ratio of (a) a unit derived from ethylene to (b) a unitderived from C3 to C20 α-olefin (hereinafter referred to sometimes as“α-olefin”), constituting the ethylene/α-olefin/non-conjugated polyenecopolymer rubber (A) (ethylene/α-olefin), is usually 60/40 to 90/10,preferably 65/35 to 90/10. When this molar ratio is in this range, avulcanized rubber molded product excellent not only in heat resistantaging, strength properties and rubber elasticity but also in coldresistance and processability can be obtained.

(ii) Iodine Value

The iodine value serving as an indicator of the content of a unitderived from non-conjugated polyene constituting theethylene/α-olefin/non-conjugated polyene copolymer rubber (A) is usually0.1 to 80 (g/100 g), preferably 5 to 50 (g/100 g). When this iodinevalue is in this range, a rubber composition of high crosslinkingefficiency is obtained, and an extrusion-molded vulcanized rubber moldedproduct excellent in compression set resistance can be obtained.

(iii) Intrinsic Viscosity

The intrinsic viscosity [η] of the ethylene/α-olefin/non-conjugatedpolyene copolymer rubber (A) measured in decalin at 135° C. is usually0.5 to 5.0 dl/g, preferably 1.0 to 4.5 dl/g. When the intrinsicviscosity [η] is in this range, a vulcanized rubber molded productexcellent not only in strength properties and compression set resistancebut also in processability can be obtained.

Specifically, the C3 to C20 α-olefin constituting theethylene/α-olefin/non-conjugated polyene copolymer rubber (A) includespropylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene,1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene,1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene,1-nonadecene, 1-eicosene, 9-methyl-1-decene, 11-methyl-1-dodecene,12-ethyl-1-tetradecene etc. These α-olefins may be used alone or as amixture of two or more thereof. Among these α-olefins, C3 to C8α-olefins such as propylene, 1-butene, 4-methyl-1-pentene, 1-hexene and1-octene are particularly preferable.

As the non-conjugated polyene constituting theethylene/α-olefin/non-conjugated polyene copolymer rubber (A), cyclic orlinear non-conjugated polyene can also be used.

The cyclic non-conjugated polyene includes, for example, dienes such asmethyltetrahydroindene, 5-ethylidene-2-norbornene,5-methylene-2-norbornene, 5-isopropylidene-2-norbornene,5-vinyl-2-norbornene, 6-chloromethyl-5-isopropenyl-2-norbornene,dicyclopentadiene and norbornadiene, and trienes such as2,3-diisopropylidene-5-norbornene,2-ethylidene-3-isopropylidene-5-norbornene and2-propenyl-2,5-norbornadiene.

The linear non-conjugated polyene includes, for example, dienes such as1,4-hexadiene and 7-methyl-1,6-octadiene and trienes such as4-ethylidene-7-methyl-1,6-nonadiene and 7-methyl-1,4,8-decatriene.

These non-conjugated polyenes can be used alone or as a mixture of twoor more thereof.

In the present invention, ethylene/α-olefin/non-conjugated polyenecopolymer rubber other than the ethylene/α-olefin/non-conjugated polyenecopolymer rubber (A) can also be used.

[Crosslinking Agent]

The crosslinking agent used in the present invention is also referred toas a vulcanizing agent, and examples include an elemental sulfur, asulfur compound, and a combination of an elemental sulfur and a sulfurcompound.

In the case of the elemental sulfur, the form of sulfur is notparticularly limited, and for example powder sulfur, precipitatedsulfur, colloidal sulfur, surface-treated sulfur, insoluble sulfur etc.can be used.

Specific examples of the sulfur compound include sulfur chloride, sulfurdichloride, high-molecular polysulfide, morpholine disulfide, alkylphenol disulfide, tetramethyl thiuram disulfide, and seleniumdimethyldithiocarbamate.

These vulcanizing agents are used in an amount of 0.01 to 10 parts byweight, preferably 0.1 to 5 parts by weight, relative to 100 parts byweight of rubber. When the vulcanizing agent is used in the above ratio,a practically usable rubber composition for vulcanized rubber moldedproducts excellent in tensile strength, elongation and sealingproperties is obtained. In a preferable embodiment, an organic peroxideis substantially not contained therein.

[Other Components]

Depending on the intended applications of vulcanized products,conventionally known additives such as polyolefin resin, rubberreinforcing agents, inorganic fillers, softening agents, aginginhibitors, processing assistants, vulcanizing accelerators, foamingagents, foaming assistants, coloring agents, dispersants andflame-retardants can be blended with the rubber composition used in thepresent invention in such a range that the object of the presentinvention is not hindered.

The rubber reinforcing agents have an effect of increasing themechanical properties of vulcanized rubber, such as tensile strength,tear strength and abrasion resistance.

Specific examples of such rubber reinforcing agents include carbon black(for example, SRF, GPF, FEF, MAF, HAF, ISAF, SAF, FT, MT), silica,activated calcium carbonate, fine talc powder, fine silicic acid powder,and silicates. These may have been subjected to surface treatment with asilane coupling agent etc.

Examples of silica include smoke silica, precipitated silica etc. Thesilica may be surface-treated with reactive silane such asmercaptosilane, aminosilane, hexamethyl disilazane, chlorosilane andalkoxysilane or with low-molecular siloxane.

The type and amount of these rubber reinforcing agents can be selectedsuitably depending on the intended applications, but usually the amountof the rubber reinforcing agents blended is up to 300 parts by weight,preferably up to 200 parts by weight, relative to 100 parts by weight ofthe rubber component.

The inorganic filers are specifically light calcium carbonate, heavycalcium carbonate, talc, clay etc.

The type and amount of these inorganic fillers can be selected suitablydepending on the intended applications, but usually the amount of theinorganic fillers blended is up to 300 parts by weight, preferably up to200 parts by weight, relative to 100 parts by weight of the rubbercomponent.

As the softening agent, a softening agent used usually in rubber can beused. Specific examples include petroleum-based softening agents such asprocess oil, lubricating oil, paraffin oil, liquid paraffin, petroleumasphalt, Vaseline etc.; coal tar-based softening agents such as coaltar, coal tar pitch etc.; fatty oil-based softening agents such ascastor oil, linseed oil, rapeseed oil, soybean oil, coconut oil etc.;toluoil; sub(factis); wax such as been molasses, carnauba wax, lanolineetc.; fatty acids and fatty acid salts such as ricinoleic acid, palmiticacid, stearic acid, barium stearate, calcium stearate, zinc laurateetc.; naphthenic acid; pine oil, rosin or derivatives thereof; syntheticpolymers such as terpene resin, petroleum resin, atactic polypropylene,chroman indene resin etc.; ester-based softening agents such as dioctylphthalate, dioctyl adipate, dioctyl sebacate etc.; and microcrystallinewax, liquid polybutadiene, modified liquid polybutadiene, liquid Thiokoland hydrocarbon-based synthetic lubricating oil. Among these materials,the petroleum-based softening agents, particularly process oil, arepreferably used.

The amount of these softening agents blended is selected suitablydepending on the applications of the vulcanized product.

The aging inhibitor includes, for example, amine-based, phenol-based orsulfur-based aging inhibitors. These aging inhibitors are used in such arange that the object of the present invention is not hindered.

As the processing assistants, processing assistants used in processingof usual rubber can be used. Specific examples include higher fattyacids such as linoleic acid, ricinoleic acid, stearic acid, palmiticacid, lauric acid etc.; higher fatty acid salts such as barium stearate,zinc stearate, calcium stearate etc.; and esters of the above high fattyacids.

The processing assistants are used in a ratio of usually 10 parts byweight or less, preferably 5 parts by weight or less, to 100 parts ofthe rubber component, but desirably the optimum amount is determineddepending on required physical properties.

The rubber composition used in the present invention may be compoundedwith a vulcanizing accelerator.

Specifically, the vulcanizing accelerator includes thiazole compoundssuch as N-cyclohexyl-2-benzothiazole sulfenamide,N-oxydiethylene-2-benzothiazole sulfenamide,N,N-diisopropyl-2-benzothiazole sulfenamide, 2-mercaptobenzothiazole,2-(2,4-dinitrophenyl)mercaptobenzothiazole,2-(2,6-diethyl-4-morpholinothio)benzothiazole, dibenzothiazyl disulfideetc.; guanidine compounds such as diphenyl guanidine, triphenylguanidine, diorthonitrile guanidine, orthonitrile biguanide, diphenylguanidine phthalate etc.; aldehydamine and aldehyde-ammonia compoundssuch as acetaldehyde/aniline reaction product, butyl aldehyde/anilinecondensate, hexamethylene tetramine, acetaldehyde ammonia, etc.;imidazoline compounds such as 2-mercaptoimidazoline etc.; thioureacompounds such as thiocarbanilide, diethyl thiourea, dibutyl thiourea,trimethyl thiourea, diorthotolylthiourea etc.; thiuram compounds such astetramethyl thiuram monosulfide, tetramethyl thiuram disulfide,tetraethyl thiuram disulfide, tetrabutyl thiuram disulfide,pentamethylene thiuram tetrasulfide etc.; dithiocarbamate compounds suchas zinc dimethyl dithiocarbamate, zinc diethyl dithiocarbamate, zincdi-n-butyl dithiocarbamate, zinc ethyl phenyl dithiocarbamate, zincbutyl phenyl dithiocarbamate, sodium dimethyl dithiocarbamate, seleniumdimethyl dithiocarbamate, tellurium dimethyl dithiocarbamate etc.;xanthene compounds such as zinc dibutyl xanthogenate etc.; and compoundssuch as zinc oxide (zinc white).

The vulcanizing accelerators may be used singly, but a combination oftwo or more thereof is preferably used.

Specific examples of the foaming agent include inorganic foaming agentssuch as sodium bicarbonate, sodium carbonate, ammonium bicarbonate,ammonium carbonate, ammonium nitrite etc.; nitroso compounds such asN,N′-dimethyl-N,N′-dinitrosoterephthalamide,N,N′-dinitrosopentamethylene tetramine etc.; azo compounds such asazodicarbonamide, azobisisobutyronitrile, azobiscyclohexyl nitrile,azodiaminobenzene, barium azodicarboxylate etc.; sulfonyl hydrazidecompounds such as benzene sulfonyl hydrazide, toluene sulfonylhydrazide, p,p′-oxybis(benzenesulfonyl hydrazide) (OBSH), diphenylsulfone-3,3′-disulfonyl hydrazide etc.; azide compounds such as calciumazide, 4,4′-diphenyl sulfonyl azide, p-toluene sulfonyl azide etc.

As the foaming agent, a plastic fine hollow body can also be used. Theplastic fine hollow body is characterized by being expanded by heating.As the plastics serving as an outer shell of the fine hollow body, thosehaving a softening temperature in a suitable range adapted to the curingtemperature of the rubber composition may be selected.

The plastics are specifically polymers or copolymers of ethylene,styrene, vinyl acetate, vinyl chloride, vinylidene chloride,acrylonitrile, butadiene, chloroprene etc.; polyamides such as nylon 6,nylon 66 etc.; polyesters such as polyethylene terephthalate etc.

To increase the expansion coefficient, a volatile solvent and a volatilesubstance such as gas are contained preferably in the plastic finehollow body.

The volatile substance is exemplified by hydrocarbons such as butane,isobutane etc.

As the plastic fine hollow body, the one having a particle size ofusually 1 to 50 μm is used, and the shape is usually spherical, but isnot particularly limited.

These foaming agents are used in an amount of usually 0.5 to 100 partsby weight, preferably 1 to 50 parts by weight, more preferably 1.5 to 40parts by weight, relative to 100 parts by weight of the rubbercomponent.

In the present invention, a foaming assistant can be used if necessaryin combination with the foaming agent. The foaming assistant acts forreducing the decomposition temperature of the foaming agent, forpromoting the decomposition of the foaming agent and for uniformfoaming.

The foaming assistant includes, for example, organic acids such assalicylic acid, phthalic acid, stearic acid, oxalic acid etc., urea orderivatives thereof.

These foaming assistants are used usually in an amount of 0 to 30 partsby weight, preferably 0 to 15 parts by weight, more preferably 0 to 10parts by weight, relative to 100 parts by weight of the rubbercomponent, but the amount is determined desirably depending on requiredphysical properties.

Liquid

In the present invention, the liquid used to adhere to the surface ofthe rubber composition is preferably a liquid containing an elementarysubstance consisting of a non-oxygen element in the group VI in theperiodic table.

The non-oxygen element in the group VI in the periodic table includes,for example, sulfur, selenium, tellurium, and polonium calcogen (elementin the oxygen group). Among these, sulfur is particularly preferable.

In addition to the elementary substance consisting of a non-oxygenelement in the group VI in the periodic table, a compound comprising thenon-oxygen element in the group VI in the periodic table may becontained in such a range that the object of the present invention canbe achieved. However, the compound comprising the non-oxygen element inthe group VI in the periodic table may not be contained. Such compoundsinclude, for example, inorganic sulfur compounds, thiazole compounds,thiuram compounds, dithiocarbamate, disulfide compounds, xanthatecompounds etc.

The element (excluding oxygen) in the VI group in the periodic table maybe solid and liquid or may be mixed with water and/or an organic solventand is used preferably as a solution and/or a dispersion.

When the dispersion is a liquid wherein the solid element (excludingoxygen) in the VI group in the periodic table is dispersed in waterand/or an organic solvent, the dispersion is referred to sometimes as asuspension.

The solvent used in the above liquid includes solvents in which theelement (excluding oxygen) in the group VI in the periodic table can bedissolved, or cannot be dissolved but can be used in a suspended stateby stirring with a mixer etc. Specific examples include water; analcohol such as methanol, ethanol and isopropyl alcohol, an organicsolvent such as benzene, toluene, xylene and chloroform, or a mixedsolvent thereof.

The liquid may contain a surfactant.

When the element (excluding oxygen) in the group VI in the periodictable is the one melted like sulfur, the element can be used as adispersion with a surfactant without using a solvent. The dispersion iscalled sometimes a suspension.

In the treatment liquid used in the present invention, it is preferablethat the element (excluding oxygen) in the group VI in the periodictable is particularly sulfur and contains a surfactant by which thesulfur is dispersed in water and/or an organic solvent.

The liquid includes, for example, a liquid containing 1 to 50 wt %elemental sulfur, 0.01 to 25 wt % dispersant, 0 to 1 wt % stabilizer and24 to 98.99 wt % water, in 100 wt % dispersion.

As the elemental sulfur, particles passing through a 300-mesh screen,preferably a 500-mesh screen, are preferably used.

The elemental sulfur is used in an amount of usually 1 to 50 wt %,preferably 5 to 30 wt %, in 100 wt % dispersion.

Dispersant

The above liquid preferably contains a surfactant as a dispersant. Asthe dispersant, a known surfactant can be used, and specifically anonionic surfactant, an anionic surfactant, a cationic surfactant and anamphoteric surfactant can be used.

The nonionic surfactant includes, for example, polyoxyalkylene alkylether, polyoxyalkylene higher alcohol ether, polyoxyalkylene alkylphenyl ether, polyoxyalkylene fatty ester, polyvalent alcohol fattyester, polyoxyalkylene polyvalent alcohol fatty ester, polyoxyalkylenefatty acid amide, sorbitan monofatty ester, sorbitan difatty ester,sorbitan trifatty ester, polyoxyalkylene sorbitan monofatty ester,polyoxyalkylene sorbitan difatty ester, polyoxyalkylene sorbitantrifatty ester, polyoxyalkylene sorbitol fatty ester, glycerin fattyester, sucrose fatty ester, polyoxyalkylene hardened castor oil,polyoxyalkylene alkylamine, polyoxyalkylene fatty acid amide, alkylamineoxide etc.

The anionic surfactant includes, for example, alkali soap, metallicsoap, organic base soap, alkyl sulfates, alkyl sulfonates, alkyl benzenesulfonates, alkyl naphthalane sulfonates, alkyl sulfosuccinates, alkylphosphates, polyoxyalkylene alkyl ether sulfates, polyoxyalkylene alkylphenyl ether sulfates, polyoxyalkylene alkyl ether sulfonates, andpolycarboxylic acid-based polymeric surfactants.

The cationic surfactants include alkylamine salts, alkyl ammonium salts,alkyl pyridinium salts etc.

The amphoteric surfactants include alkyl betaine, aminocarboxylic acids,alkyl β-alanine, imidazoline etc.

These surfactants can be used singly or as a combination of two or morethereof. From the viewpoint of the shelf stability of the finallyobtained dispersion, a nonionic surfactant containing ether oxygen ispreferably used.

The surfactant is used in an amount of usually 1 to 50 parts by weight,preferably 10 to 30 parts by weight, relative to 100 parts by weight ofthe elemental sulfur.

Specifically, the dispersant is contained in an amount of usually 0.01to 25 wt %, preferably 1 to 6 wt %, relative to 100 wt % of the liquid.

Stabilizer

The liquid which can be used in the present invention can contain astabilizer if necessary. As the stabilizer, it is possible to use knownstabilizers if necessary, among which polyvinyl alcohol (completelysaponified or partially saponified, a polymerization degree of 1000 to1700), polyethylene glycol, polypropylene glycol, ethylene glycol,propylene glycol copolymer, carboxymethyl cellulose and sodiumpolyacrylate are preferable, and polyvinyl alcohol (completelysaponified, a polymerization degree of 1500 to 1700) is particularlypreferable.

The stabilizer is used desirably in an amount of usually 0 to 10 partsby weight, preferably 0 to 5 parts by weight, relative to 100 parts byweight of the elemental sulfur.

Specifically, the stabilizer is contained in an amount of usually 0 to 1wt %, preferably 0 to 0.5 wt %, relative to 100 wt % of the liquid.

Dispersing Medium

In the above liquid, a predetermined solvent may be used as thedispersing medium. The solvent used may be any known solvent insofar asit does not react with the elemental sulfur and non-crosslinked rubberto be crosslinked and can dissolve or disperse a dispersant andstabilizer described later.

Specific examples include water, organic solvents such as methanol,ethanol, isopropyl alcohol, acetone, hexane, heptane, benzene, tolueneand xylene, and oil. These may be used alone or as a mixture of two ormore thereof. Among these, water is preferable from the viewpoint ofstorage and safety. As water, water subjected to purification treatment,such as deionized water, purified water etc., is preferably used.

The dispersing medium is used desirably in an amount of usually 200 to10000 parts by weight, preferably 286 to 2000 parts by weight, relativeto 100 parts by weight of the elemental sulfur.

Method of Producing the Vulcanized Rubber Molded Product

In the method of producing the vulcanized rubber molded product(non-foamed product, foamed product) according to the present invention,a non-vulcanized rubber composition (including a non-vulcanizednon-foamed rubber composition) is first prepared.

The non-vulcanized rubber composition used in the present invention canbe prepared for example by kneading rubber (for exampleethylene/α-olefin/non-conjugated polyene copolymer rubber) and ifnecessary additives such as a rubber reinforcing agent, an inorganicfiller and a softening agent at a temperature of 80 to 170° C. for 2 to20 minutes in a Banbury mixer, a kneader, an internal mixer such asintermix (closed mixer) and then mixing the resulting mixture withsulfur (vulcanizing agent) and if necessary a vulcanizing accelerator,or sulfur (vulcanizing agent) and if necessary a vulcanizingaccelerator, a foaming agent and a foaming assistant, in a roll such asan open roll or a kneader and kneading the mixture at a roll temperatureof 40 to 80° C. for 5 to 30 minutes, followed by gaging.

In the present invention, the non-vulcanized rubber compositioncontaining rubber, a crosslinking agent and if necessary other additivessuch as a foaming agent is extruded usually via an extruder equippedwith a die to form an intended product of predetermined shape andcontinuously vulcanized or vulcanized and foamed.

As the extruder, an extruder used for rubber can be usually used.

The shape of the product is not particularly limited, and for example,the shape of a weather strip, a glass run channel, an opening trim, or ahose can be mentioned. The non-vulcanized rubber composition is endowedwith a desired product shape by extruding it through the die of theextruder usually.

In the present invention, droplets or spray of the treatment liquid areallowed to adhere to the surface of the non-vulcanized rubbercomposition having a predetermined shape while being discharged from theextruder and reaching a vulcanizing bath.

The treatment liquid is sprayed onto the surface of the non-vulcanizedrubber composition having a product shape to form a coating thereon, andthen the non-vulcanized rubber composition is introduced into avulcanizing bath and heated at a temperature of 120 to 270° C. for 1 to30 minutes, whereby the composition can be vulcanized or vulcanized andfoamed. The step of vulcanization or vulcanization foaming is carriedout usually continuously.

In the present invention, it is preferable that a coating of thetreatment liquid is formed on the surface of the non-vulcanized rubbercomposition having a product shape, but spots of the treatment liquidmay be formed on a minute part of the non-vulcanized rubber composition.

When the element (excluding oxygen) in the group VI in the periodictable, contained in the treatment liquid, is sulfur, the sulfur issubstantially insoluble in any of the above solvents, and thus adispersion, for example a suspension, is used preferably as thetreatment liquid.

The method of allowing droplets or spray of the liquid containing theelement (excluding oxygen) in the group VI in the periodic table toadhere to the surface of the non-vulcanized rubber composition is notparticularly limited, and for example, droplets or spray generated by aspraying machinery can be brought directly or indirectly into contactwith the surface of the non-vulcanized rubber composition.

The droplets and spray are evident to those skilled in the art. In thepresent invention, the size of droplets or spray is not particularlylimited, but is preferably 1000 μm or less.

The surface of the non-vulcanized rubber composition to which thetreatment liquid adheres may be throughout the product, but in respectof design, it is preferable that the treatment liquid adheres to theexternal surface of the product. The treatment liquid may also adhere tothe internal surface of the product, but even if the treatment liquiddoes not adhere to the internal surface, there may not be any problem inrespect of design.

The heating method in the vulcanizing bath includes, for example,heating means such as a heated air vulcanizing bath (HAV), a glass beadsfluidized bed, an ultra-high frequency vulcanizing device (UHF), andsteam can be used. The continuous extrusion line is preferably acombination of an extruder→spraying machinery→UHF→HAV or a combinationof an extruder→spraying machinery→HAV→UHF→HAV.

In the method of producing the crosslinked rubber molded productaccording to the present invention, droplets or spray of the treatmentliquid can adhere to the surface of the non-vulcanized rubbercomposition before the non-vulcanized rubber composition is shaped in apredetermined product shape.

For example, the treatment liquid is side-fed to a die, head or barrelof the rubber extruder and poured directly into the non-vulcanizedrubber material before attaining a predetermined shape, whereby thetreatment liquid can adhere to the surface (contacting with the die) ofthe rubber material having a predetermined shape after extrusion.

In the present invention, it is preferable in respect of productivitythat the process is carried out successively from the step of shapingthe non-vulcanized rubber composition in a predetermined product shapeto the step of vulcanizing or vulcanizing foaming step.

According to the method of the present invention, it is possible toobtain a vulcanized rubber molded product wherein the amount of sulfuratoms present in the surface of the vulcanized rubber molded product isat least 1.2 times as high as the amount of sulfur atoms present in acut face obtained by cutting the surface to a depth of 1.0 mm in thevertical direction.

In the method of producing the vulcanized rubber molded productaccording to the present invention, the improvement of foaming ispreferably 1% or more. The improvement of foaming will be described inthe Examples.

The vulcanized rubber molded product produced by the method of thepresent invention is preferably extruded sponge rubber or extruded solidrubber.

The vulcanized rubber molded product produced by the method of thepresent invention is preferably a foamed product having a specificgravity of 0.8 to 0.01, particularly 0.80 to 0.20, and a surfaceroughness (RzD) of 10 μm or less. This foamed product is used preferablyin application to automobile weather strip sponge.

The automobile weather strip includes a composite product consisting ofsponge rubber/solid rubber/metal. The sponge rubber and solid rubber aredifferent from each other in respect of composition and are thusdifferent from each other in the rate of vulcanization reaction uponheating in the vulcanizing bath, so that when the molding conditions areadapted to the side of the sponge rubber material, the design andphysical properties of the solid rubber material are deteriorated, whilewhen the conditions are adapted to the side of the solid rubbermaterial, there frequently occur inconveniences in the side of thesponge material. Without using such composite products made of differentmaterials, both rubber physical properties and design can be realized athigh levels by the present invention.

The vulcanized rubber molded product produced by the method of thepresent invention is preferably a foamed product having a specificgravity of 0.81 to 1.10 and a surface roughness (RzD) of 6 μm or less.This foamed product is preferably finely foamed solid.

The method of measuring the specific gravity and surface roughness (RzD)will be described in the Examples.

The vulcanized rubber molded product is used preferably in anyapplication selected from the group consisting of a weather strip, aglass run channel, an opening trim and a hose.

The extruded sponge includes, for example, highly foamed sponge, weatherstrip sponge, a finely foamed glass run channel, a finely foamed hose,etc.

The extruded solid includes, for example, a glass run channel, a trim,draining rubber, window frame sealing rubber, etc.

In the present invention, the vulcanized rubber molded product ispreferably a foamed product.

The vulcanized rubber molded product of the present invention is used inautomobile applications such as glass run channel products, window frameproducts, draining products, laces, automobile roofs, a sealing partaround a trunk, hoses, foamed products, and rubber vibration insulatorssuch as damper pulleys, engine mounts, strut mounts, muffler hangers,bushes etc. The vulcanized rubber molded product is also used inbuilding materials such as sash gaskets, building joint products andhighly foamed sponge.

EXAMPLES

Hereinafter, the present invention is described in more detail byreference to the Examples, but the present invention is not limited tothe Examples.

The method of measuring physical properties of copolymer rubber used inthe Examples and Comparative Examples and physical properties of theresulting vulcanized rubber products is as follows.

(1) Improvement of Foaming Efficiency

The improvement of foaming efficiency was calculated according to thefollowing equation:

Improvement of foaming efficiency (%)=(1−r_(B)/r_(A))×100 wherein r_(A)is the specific gravity of a tubular or string vulcanized rubber foamedmolded product produced without application of the surface treatmenttechnique using the treatment liquid of the present invention, and r_(B)is the specific gravity of a tubular or string vulcanized rubber foamedmolded product produced by using this technique.

(2) Specific Gravity

From a tubular or string vulcanized rubber (foamed) molded productvulcanized with hot air, a 20 mm×20 mm test specimen was punched off andsmuts on the surface were wiped away with alcohol.

Using an automatic specific gravity meter (M-1 type automatic specificgravity meter manufactured by Toyo Seiki Seisaku-sho, Ltd.), thespecific gravity (SG) of the test specimen in an atmosphere at 25° C.was determined by calculating the difference between the weight of thetest specimen in air and the weight of the test specimen in purifiedwater.

(3) Water Absorptivity

From a tubular or string vulcanized rubber foamed molded productvulcanized with hot air, a 20 mm×20 mm test specimen was punched off andsmuts on the surface were wiped away with alcohol.

Then, distilled water was introduced into a container capable ofdecompression, and the test specimen was dipped in a position 50 mmbelow the water surface, and then the air on the water surface wasdecompressed to 130 mmHg with a rotary pump and then maintained for 3minutes. Then, the pressure was returned to the atmospheric pressure,and 3 minutes later, the weight of the test specimen having adsorbedwater was measured, and the water adsorptivity (Wa) was calculated fromthe following equation:Wa (%)={(W2−W1)/W1}×100wherein W1 is the weight (g) of the test specimen before dipping, and W2is the weight (g) of the test specimen after dipping.(4) Compression Set (CS)

A tubular or string vulcanized rubber (foamed) molded product vulcanizedwith hot air was cut into a test specimen having a length of 30 mm, andthen attached to a jig for measuring compression set.

Then, the test specimen was compressed such that the height of the testspecimen was reduced to ½ relative to the height before application ofloading, and the specimen together with the jig was placed in a gearoven at 70° C. and heat-treated for 200 hours.

After heat treatment, the test specimen was removed from the compressingmachine and then cooled for 30 minutes, and the height of the testspecimen was measured, and the compression set (CS) was calculated fromthe following equation:CS (%)=[(t ₀ −t ₁)/(t ₀ −t ₂)]×100wherein

-   -   t₀: height of the test specimen before the test.    -   t₁: height of the test specimen which was heat-treated and then        left and cooled for 30 minutes.    -   t₂: height of the test specimen attached to the measurement jig.        (5) Surface Roughness (RzD)

A tubular or string vulcanized rubber (foamed) molded product obtainedby continuous extrusion vulcanizing molding was cut into a test specimenof 30 mm in length to prepare a surface roughness measurement sample.Surface roughness was measured by using a surface roughness metermanufactured by Tokyo Seimitsu Co., Ltd. Specifically, the needle top ofthe surface roughness meter was placed on the top of the tubular orstring vulcanized rubber (foamed) molded product, and a surfaceroughness test was conducted under the conditions of a scanning rate of0.3 mm/s and a scanning range of 1 cm. The surface roughness (RzD; unitμm) was determined according to JIS B 0601.

(6) Shape Retention

Tubular sponge rubber vulcanized with continuous hot air vulcanizationwas cut into a specimen having a length of 2 mm, and using a magnifyingglass, length A and width B were measured respectively as the innerdiameter of the tubular sponge rubber 1 shown in FIG. 1, and the shaperetention was calculated from the following equation.Shape retention (%)=[(dimension of length A)/(dimension of width B)]×100(7) Evaluation of Abrasion Resistance

Using an abrasion testor manufactured by Ueshima Seisakusho Co., Ltd.,abrasion resistance was evaluated under the following evaluationcriteria after rubbing a test specimen 100 times with sand paper #80under a loading of 500 g.

-   Evaluation 1: Deep traces of sand paper remain in the rubbing    direction, and the rubber is shaved.-   Evaluation 2: Slight traces of sand paper remain in the rubbing    direction, and there are parts where the rubber is shaved.-   Evaluation 3: No traces of sand paper remain in the rubbing    direction, and there is no part where the rubber is shaved.    (8) Tensile Strength and Elongation

A test specimen was obtained by punching in No. 3 dumbbell shapedescribed in JIS K6301 (1989).

This test specimen was examined in a tensile test at a measurementtemperature of 25° C. at a stress rate of 500 mm/min. according to amethod stipulated under JIS K6301, Item 3, to determine tensile strength(T_(B)) and elongation (E_(B)).

(9) Quantification of Sulfur Atoms Present in the Surface and the Insideof the Vulcanized Rubber Molded Product

The surface of the rubber product was washed 5 times or more with newabsorbent cotton impregnated with ethanol, and then dried, and X rayphotoelectron spectroscopy (XPS) with SSX-100 manufactured by SSI todetermine its elemental composition. The X-ray source used wasmonochromatic AlKα. Integration was conducted 200 times.

The amount of sulfur atoms present in the inside of the vulcanizedrubber molded product was determined by cutting the surface of themolded product to a depth of 1.0 mm in the vertical direction to form acut face having a size of 10 mm×10 mm, and then analyzing the cut face.That is, the analysis of the internal surface of the vulcanized rubbermolded product was conducted.

The ethylene/propylene/non-conjugated polyene copolymer rubbers used inthe Examples and Comparative Examples are as follows.

(1) Ethylene/Propylene/Non-Conjugated Polyene Copolymer Rubber (EPT-A)Manufactured by Mitsui Chemicals, Inc.

-   -   Ethylene/propylene molar ratio: 68/32    -   Non-conjugated polyene: 5-ethylidene-2-norbornene (ENB)    -   Iodine value: 24 (g/100 g)    -   Intrinsic viscosity [η] measured in decalin at 135° C.: 1.7        dl/g.        (2) Ethylene/Propylene/Non-Conjugated Polyene Copolymer Rubber        (EPT-B) Manufactured by Mitsui Chemicals, Inc.    -   Ethylene/propylene molar ratio: 68/32    -   Non-conjugated polyene: 5-ethylidene-2-norbornene (ENB)    -   Iodine value: 13 (g/100 g)    -   Intrinsic viscosity [η] measured in decalin at 135° C.: 1.7        dl/g.        (3) Ethylene/Propylene/Non-Conjugated Polyene Copolymer Rubber        (EPT-C) Manufactured by Mitsui Chemicals, Inc.    -   Ethylene/propylene molar ratio: 63/37    -   Non-conjugated polyene: 5-ethylidene-2-norbornene (ENB)    -   Iodine value: 22 (g/100 g)    -   Intrinsic viscosity [η] measured in decalin at 135° C.: 1.5        dl/g.        (4) Ethylene/Propylene/Non-Conjugated Polyene Copolymer Rubber        (EPT-D) Manufactured by Mitsui Chemicals, Inc.    -   Ethylene/propylene molar ratio: 65/35    -   Non-conjugated polyene: DCPD    -   Iodine value: 22 (g/100 g)    -   Intrinsic viscosity [η] measured in decalin at 135° C.: 2.8        dl/g.

Example 1

[Preparation of Non-Vulcanized Non-Foamed Rubber Composition andVulcanized Rubber Foamed Product]

First, 120.0 parts by weight of ethylene/propylene/non-conjugatedpolyene copolymer rubber (EPT-A) were masticated for 30 seconds, andthen 5.0 parts by weight of zinc white No. 1, 1.0 part by weight ofstearic acid and 50.0 parts by weight of a softening agent [trade name:Dianaprocess PW-380, paraffin oil manufactured by Idemitsu Kosan Co.,Ltd.] were added thereto, and finally 90.0 parts by weight of SRF carbonblack [trade name: Asahi #50HG, manufactured by Asahi Carbon Co., Ltd.]were added thereto and kneaded for 4 minutes, and the resulting compoundwas discharged. The temperature of the compound after discharge was 150to 170° C. The kneading was carried out in a Banbury mixer having avolume of 16 L (manufactured by Kobe Steel, Ltd.) in a charging degreeof 70%.

Then, this compound was wound on 14-inch open rolls (the surfacetemperature of a former roll, 50° C.; the surface temperature of alatter roll, 50° C.; number of revolutions of the former roll, 16 rpm;the number of revolutions of the latter roll, 18 rpm), and 1.5 parts ofa vulcanizing agent sulfur, 2.0 parts of 2-mercaptobenzothiazole (MBT)[trade name: Sunseller MBT manufactured by Sanshin Chemical IndustryCo., Ltd.], 1.25 parts by weight of zinc dibutyldithiocarbamate (ZnBDC)[trade name: Sunseller ZnBDC manufactured by Sanshin Chemical IndustryCo., Ltd.], 0.25 parts by weight of zinc dimethyldithiocarbamate (ZnMDC)[trade name: Sunseller ZnMDC manufactured by Sanshin Chemical IndustryCo., Ltd.] and 1.0 part by weight of 2-mercapto-2-imidazoline (EU)[trade name: Sunseller EU manufactured by Sanshin Chemical Industry Co.,Ltd.] as vulcanizing accelerators, 4.0 parts by weight of an OBSH-basedfoaming agent [trade name: Neocerbon #N1000SW manufactured by EiwaChemical Ind. Co., Ltd.] and 2.0 parts by weight of a hygroscopic agent[trade name: Besta #20 manufactured by Inoue Sekkai Kogyo Co., Ltd.]were added thereto and dispersed and kneaded for 6 minutes, and thekneaded product was gaged into a ribbon of 10 mm in thickness and 70 mmin width to give a non-vulcanized non-foamed rubber composition.

As shown in FIG. 2, the rubber composition thus obtained was introducedinto a φ60 mm rubber extruder 2, and then the extruded non-vulcanizednon-foamed rubber composition 3 was passed through a spraying device 4and passed continuously through a molding line wherein a vulcanizingbath 7 (180° C., 4 kW) and a heated air vulcanizing bath (HAV) 8 (240°C., 5 minutes) were connected in series in an ultra-high frequencyvulcanizing device (UHF), whereby the tubular non-vulcanized rubberhaving an inner diameter of 10 mm and an outer diameter of 11 mm(thickness 1 mm), extruded through a die of the rubber extruder, wasvulcanized and foamed to give sponge rubber.

The rate of the conveyor belt was regulated such that the extruder 2 wasat a rate of 2.5 m/min., the UHF 7 outlet was 2.7 m/min., the HAV 8outlet was 2.9 m/min., and a take-off unit (not shown) was 3.2 m/min.

A treatment liquid (1) 6 prepared in a manner described later wassprayed by the spraying device 4 onto the surface of the non-vulcanizednon-foamed rubber composition 3 until the non-vulcanized non-foamedrubber composition 3 reached the UHF vulcanizing bath 7. In the sprayingmethod, a compressor was combined with a pressure-sending tank, and aspraying gun (HM-3: nozzle diameter 1.0 mm) 5 manufactured by Fuso SeikiCo., Ltd. was used.

[Preparation of Treatment Liquid (1)]

Weighed powdery sulfur (Karuizawa Seirensho) was added to water, and asurfactant [polymethacrylic acid and dodecyl trimethyl ammonium bromide]was added thereto, and this mixture was passed through a mesh 500 toremove powdery sulfur aggregates, whereby a spraying suspension wasobtained. This suspension was used as the treatment liquid (1).

The composition of the treatment liquid (1) obtained in this manner was10 wt % powdery sulfur (vulcanizing agent), 85.8 wt % water, and 4.2 wt% surfactant (2.0 wt % polymethacrylic acid and 2.2 wt % dodecyltrimethyl ammonium bromide).

For the above preparation method, “Suiyosei Kobunshino Saishin Gijyutsu”(Newest Technology of Water-Soluble Polymer) (published by CMC andauthored by Teruo Horiuchi, p. 23 (2000)) was referred to.

According to the methods described above, the vulcanized rubber foamedproduct (weather strip sponge) obtained in the manner described abovewas measured for the surface roughness of the product, the surfaceroughness of the internal surface of the hollow, shape retention,tensile strength at break (T_(B)) elongation (E_(B)), compression set(CS), abrasion resistance, specific gravity, improvement of foamingefficiency, water absorptivity, and the amount of sulfur present in thesurface and the inside of the product.

The results are shown in Table 1.

Example 2

A tubular vulcanized rubber foamed product (weather strip spongeproduct) was obtained in the same manner as in Example 1 except that atreatment liquid (2) having the following composition, prepared in thesame manner as in the method of preparing the treatment liquid (1) wasused in place of the treatment liquid (1).

The composition of the treatment liquid (2) was 5 wt % powdery sulfur(vulcanizing agent), 5 wt % tetramethyl thiuram disulfide (vulcanizingaccelerator) [trade name: Sunseller TT manufactured by Sanshin ChemicalIndustry Co., Ltd.], 85.8 wt % water, and 4.2 wt % surfactant (2.0 wt %polymethacrylic acid and 2.2 wt % dodecyl trimethyl ammonium bromide).

According to the methods described above, the vulcanized rubber foamedproduct thus obtained was measured for the surface roughness of theproduct, the surface roughness of the internal surface of the hollow,shape retention, tensile strength at break (T_(B)), elongation (E_(B)),compression set (CS), abrasion resistance, specific gravity, improvementof foaming efficiency, water absorptivity, and the amount of sulfurpresent in the surface and the inside of the product.

The results are shown in Table 1.

Example 3

A tubular vulcanized rubber foamed product (weather strip spongeproduct) was obtained in the same manner as in Example 1 except that atreatment liquid (3) having the following composition prepared in thesame manner as in the method of preparing the treatment liquid (1) wasused in place of the treatment liquid (1).

The composition of the treatment liquid (3) was 5 wt % powdery sulfur(vulcanizing agent), 5 wt % zinc-di-n-butyl dithiocarbonate (vulcanizingaccelerator) [trade name: Sunseller Bz manufactured by Sanshin ChemicalIndustry Co., Ltd.], 85.8 wt % water, and 4.2 wt % surfactant (2.0 wt %polymethacrylic acid and 2.2 wt % dodecyl trimethyl ammonium bromide).

According to the methods described above, the vulcanized rubber foamedproduct thus obtained was measured for the surface roughness of theproduct, the surface roughness of the internal surface of the hollow,shape retention, tensile strength at break (T_(B)), elongation (E_(B)),compression set (CS), abrasion resistance, specific gravity, improvementof foaming efficiency, water absorptivity, and the amount of sulfurpresent in the surface and the inside of the product.

The results are shown in Table 1.

Example 4

A non-vulcanized non-foamed rubber composition was obtained in the samemanner as in Example 1 except that the amount of the foaming agentblended was changed from 4.0 parts by weight to 2.0 parts by weight.

Using this rubber composition, a tubular vulcanized rubber foamedproduct (weather strip sponge product) was obtained in the same manneras in Example 1.

According to the methods described above, the vulcanized rubber foamedproduct thus obtained was measured for the surface roughness of theproduct, the surface roughness of the internal surface of the hollow,shape retention, tensile strength at break (T_(B)), elongation (E_(B)),compression set (CS), abrasion resistance, specific gravity, improvementof foaming efficiency, water absorptivity, and the amount of sulfurpresent in the surface and the inside of the product.

The results are shown in Table 1.

Comparative Example 1

A tubular vulcanized rubber foamed product (weather strip spongeproduct) was obtained in the same manner as in Example 1 except that thesurface treatment with the treatment liquid (1) was not conducted.

According to the methods described above, the vulcanized rubber foamedproduct thus obtained was measured for the surface roughness of theproduct, the surface roughness of the internal surface of the hollow,shape retention, tensile strength at break (T_(B)), elongation (E_(B)),compression set (CS), abrasion resistance, specific gravity, improvementof foaming efficiency, water absorptivity, and the amount of sulfurpresent in the surface and the inside of the product.

The results are shown in Table 1.

Comparative Example 2

A tubular vulcanized rubber foamed product (weather strip spongeproduct) was obtained in the same manner as in Example 4 except that thesurface treatment with the treatment liquid (1) was not conducted.

According to the methods described above, the vulcanized rubber foamedproduct thus obtained was measured for the surface roughness of theproduct, the surface roughness of the internal surface of the hollow,shape retention, tensile strength at break (T_(B)), elongation (E_(B)),compression set (CS), abrasion resistance, specific gravity, improvementof foaming efficiency, water absorptivity, and the amount of sulfurpresent in the surface and the inside of the product.

The results are shown in Table 1. TABLE 1 Comparative ComparativeExample 1 Example 2 Example 3 Example 4 Example 1 Example 2 Treatmentliquid (1) (2) (3) (1) Not treated Not treated Method of applying theSpray Spray Spray Spray treatment liquid system system system systemSurface roughness (μm) Surface of the product 5 3 3 5 18 17 Internalsurface of the 22 22 22 22 22 19 hollow in the product Shape retention(%) 85 82 80 88 65 62 Mechanical strength properties TB (MPa) 3.8 3.93.9 4.3 3.2 3.8 EB (%) 280 290 290 350 240 260 Compression set (%) 14 1515 14 20 22 Evaluation of abrasion 3 3 3 3 1 1 resistance EvaluationSpecific gravity 0.42 0.41 0.41 0.61 0.48 0.7 Improvement of foaming 1315 15 13 0 0 efficiency (%) Water adsorptivity (%) 0.5 0.8 0.7 0.5 35 29Amount of present sulfur (atom-%) Surface of the product 0.6 0.5 0.5 0.50.2 0.2 Inside of the product 0.3 0.3 0.3 0.3 0.3 0.3 Ratio of presentsulfur 2.0 1.7 1.7 1.7 0.7 0.7

From Table 1, the following can be understood.

The vulcanized rubber foamed product in Example 1 obtained by thesurface treatment method of spraying the sulfur suspension (treatmentliquid (1)) onto the surface of the non-vulcanized non-foamed rubbercomposition is extremely superior in surface smoothness to thevulcanized rubber foamed product in Comparative Example 1 obtainedwithout using the surface treatment method. This is because by sprayingthe treatment liquid (1), the concentration of the vulcanizing agent inthe surface of the non-vulcanized non-foamed rubber composition becomesso high that the vulcanization reaction proceeds rapidly. The surfacerapidly forms a vulcanized rubber state, and as a result, thedeformation of the extruded product (deterioration in shape retention)by heating in the vulcanizing bath is relaxed, and high shape retentionand low water adsorptivity can be achieved. Further, the leakage of gascaused by the foaming agent from the surface of the non-vulcanizednon-foamed rubber composition is reduced, and thus the specific gravityis reduced. That is, the foaming agent may be added in a smaller amountto achieve desired specific gravity, thus contributing to reducing thecost. The improvement of foaming efficiency in the vulcanized rubberfoamed product in Example 1 was 13%.

From the results in Examples 2 and 3, it was revealed that the sameeffect was also achieved when the type of the suspension was changed.

Example 4 is the case where the amount of the defoaming agent wasreduced from 4 phr to 2 phr. The effect of the present invention canalso be achieved even if the amount of the defoaming agent was reduced,as compared with Comparative Example 2 where the amount of the defoamingagent was similarly reduced.

In Examples 1 to 4 where the treatment liquid of the present inventionis used, the mechanical strength, elongation, compression set, andabrasion resistance of the vulcanized rubber foamed product areimproved. It is understood that the surface smoothness index RzD of apart not coated with the treatment liquid of the present invention issignificantly improved as compared with the vulcanized rubber foamedproducts obtained in Comparative Examples 1 and 2 where the treatmentliquid of the present invention is not used.

When the amount of sulfur present in the surface of the vulcanizedrubber is at least 1.2 times as high as the amount of sulfur present inthe surface and the inside of the vulcanized rubber, excellent rubberphysical properties and design are exhibited. The amount of sulfurpresent in the surface of the vulcanized rubber foamed products obtainedin Comparative Examples 1 and 2 is low and identical with the amount ofsulfur present in the inside of the products.

Example 5

[Preparation of Non-Vulcanized Non-Foamed Rubber Composition andVulcanized Rubber Foamed Product]

First, 110.0 parts by weight of ethylene/propylene/non-conjugatedpolyene copolymer rubber (EPT-B) were masticated for 30 seconds, andthen 5.0 parts by weight of zinc white No. 1, 1.0 part by weight ofstearic acid and 55.0 parts by weight of a softening agent [trade name:Dianaprocess PW-380, paraffin oil manufactured by Idemitsu Kosan Co.,Ltd.] were added thereto, and finally 170.0 parts by weight of FEFcarbon black [trade name: Asahi #60G, manufactured by Asahi Carbon Co.,Ltd.] and 15.0 parts by weight of heavy calcium carbonate [trade name:Whitone SB manufactured by Shiraishi Calcium Kaisha, Ltd.] were addedthereto and kneaded for 4 minutes, and the resulting compound wasdischarged. The temperature of the compound after discharge was 150 to170° C. The kneading was carried out in a Banbury mixer having a volumeof 16 L (manufactured by Kobe Steel, Ltd.) in a charging degree of 70%.

Then, this compound was wound on 14-inch open rolls (the surfacetemperature of a former roll, 50° C.; the surface temperature of alatter roll, 50° C.; number of revolutions of the former roll, 16 rpm;the number of revolutions of the latter roll, 18 rpm), and 0.8 part of avulcanizing agent sulfur, 1.0 part of2-(4′-morpholinodithio)benzothiazole (MDB) [trade name: Nocseller MDMmanufactured by Ouchishinko Chemical Industrial Co., Ltd.], 0.4 part byweight of tetrabutyl thiuram disulfide (TBTD) [trade name: SunsellerTBTD manufactured by Sanshin Chemical Industry Co., Ltd.], 0.4 part byweight of zinc dibutyldithiocarbamate (ZnBDC) [trade name: SunsellerZnBDC manufactured by Sanshin Chemical Industry Co., Ltd.] and 0.4 partby weight of 2-mercapto-2-imidazoline (EU) [trade name: Sunseller EUmanufactured by Sanshin Chemical Industry Co., Ltd.] as vulcanizingaccelerators, 0.5 part by weight of an OBSH-based foaming agent [tradename: Neocerbon #N1000SW manufactured by Eiwa Chemical Ind. Co., Ltd.]and 5.0 parts by weight of a hygroscopic agent [trade name: Besta #BSmanufactured by Inoue Sekkai Kogyo Co., Ltd.] were added thereto anddispersed, and kneaded for 6 minutes, and the kneaded product was gagedinto a ribbon of 10 mm in thickness and 70 mm in width to give anon-vulcanized non-foamed rubber composition.

As shown in FIG. 2, the rubber composition thus obtained was introducedinto a φ60 mm rubber extruder 2, and then the extruded non-vulcanizednon-foamed rubber composition 3 was passed through a spraying device 4and passed continuously through a molding line wherein a vulcanizingbath 7 (180° C., 4 kW) and a heated air vulcanizing bath (HAV) 8 (240°C., 5 minutes) were connected in series in an ultra-high frequencyvulcanizing device (UHF), to give a cylindrical vulcanized rubber foamedproduct (slightly foamed solid product (finely foamed sponge product))having a diameter of 9 mm.

The rate of the conveyor belt was regulated such that the extruder 2 wasat a rate of 2.5 m/min., the UHF 7 outlet was 2-0.7 m/min., the HAV 8outlet was 2.9 m/min., and a take-off unit (not shown) was 3.2 m/min.

The treatment liquid (1) 6 was sprayed by the spraying device 4 onto thesurface of the non-vulcanized non-foamed rubber composition 3 until thenon-vulcanized non-foamed rubber composition 3 reached the UHFvulcanizing bath 7. In the spray method, a compressor was combined witha pressure-sending tank, and a spraying gun (HM-3: nozzle diameter 1.0mm) 5 manufactured by Fuso Seiki Co., Ltd. was used.

According to the methods described above, the solid product thusobtained was measured for the surface roughness of the product, tensilestrength at break (T_(B)), elongation (E_(B)) compression set (CS),abrasion resistance, specific gravity, improvement of foamingefficiency, water absorptivity, and the amount of sulfur present in thesurface and the inside of the product.

The results are shown in Table 2.

Example 6

A non-vulcanized non-foamed rubber composition was prepared in the samemanner as in Example 5 except that the amount of the foaming agentblended was changed from 0.5 part by weight to 0.2 part by weight.

Using this rubber composition, a cylindrical vulcanized rubber foamedproduct (slightly foamed solid product (finely foamed sponge product))having a diameter of 9 mm was obtained in the same manner as in Example5.

According to the methods described above, the solid product thusobtained was measured for the surface roughness of the product, tensilestrength at break (T_(B)), elongation (E_(B)), compression set (CS),abrasion resistance, specific gravity, improvement of foamingefficiency, water absorptivity, and the amount of sulfur present in thesurface and the inside of the product.

The results are shown in Table 2.

Comparative Example 3

A cylindrical vulcanized rubber foamed product (slightly foamed solidproduct (finely foamed sponge product)) having a diameter of 9 mm wasprepared in the same manner as in Example 5 except that the surfacetreatment with the treatment liquid (1) was not conducted.

According to the methods described above, the solid product thusobtained was measured for the surface roughness of the product, tensilestrength at break (T_(B)), elongation (E_(B)), compression set (CS),abrasion resistance, specific gravity, improvement of foamingefficiency, water absorptivity, and the amount of sulfur present in thesurface and the inside of the product.

The results are shown in Table 2.

Comparative Example 4

A cylindrical vulcanized rubber foamed product (slightly foamed solidproduct (finely foamed sponge product)) having a diameter of 9 mm wasprepared in the same manner as in Example 6 except that the surfacetreatment with the treatment liquid (1) was not conducted.

According to the methods described above, the solid product thusobtained was measured for the surface roughness of the product, tensilestrength at break (T_(B)), elongation (E_(B)), compression set (CS),abrasion resistance, specific gravity, improvement of foamingefficiency, water absorptivity, and the amount of sulfur present in thesurface and the inside of the product.

The results are shown in Table 2. TABLE 2 Com- Com- parative parativeExample 5 Example 6 Example 3 Example 4 Treatment liquid (1) (1) Not Nottreated treated Method of applying the Spray Spray treatment liquidsystem system Surface roughness (μm) Surface of the product 5 5 25 19Mechanical strength properties TB (MPa) 10.2 11.2 8.7 9.1 EB (%) 300 330270 260 Compression set(%) 30 34 45 47 Evaluation of abrasion 3 3 2 2resistance Evaluation Specific gravity 0.88 0.95 0.95 1.01 Improvementof foaming 7 6 0 0 efficiency(%) Water adsorptivity (%) 0.1 0.1 0.2 0.1Amount of present sulfur (atom-%) Surface of the product 0.5 0.5 0.2 0.2Inside of the product 0.2 0.2 0.2 0.2 Ratio of present sulfur 2.5 2.51.0 1.0

From Table 2, the following can be understood.

In preparation of the non-vulcanized non-foamed rubber composition, 0.5part of OBSH-based foaming agent was blended in Example 5, and 0.2 partof OBSH-based foaming agent was blended in Example 6. In ComparativeExample 3 corresponding to Example 5 and in Comparative Example 4corresponding to Example 6, the surface treatment method in the presentinvention is not used. In the finely foamed sponge products (slightlyfoamed solid products) obtained in Comparative Examples 3 and 4, theratio of present sulfur is 1.0, and the products are poor in surfacesmoothness. On the other hand, the finely foamed sponge productsobtained in Examples 5 and 6 wherein the ratio of present sulfur is 2.5are superior in mechanical strength and elongation to the finely foamedsponge products obtained in Comparative Examples 3 and 4, and improveabrasion resistance.

Example 7

[Preparation of Non-Vulcanized Non-Foamed Rubber Composition andVulcanized Rubber Foamed Product]

First, 100.0 parts by weight of ethylene/propylene/non-conjugatedpolyene copolymer rubber (EPT-C) were masticated for 30 seconds, andthen 5.0 parts by weight of zinc white No. 1, 2.0 parts by weight ofstearic acid and 50.0 parts by weight of a softening agent [trade name:Dianaprocess PW-380, paraffin oil manufactured by Idemitsu Kosan Co.,Ltd.] were added thereto, and finally 50.0 parts by weight of SRF carbonblack [trade name: Asahi #50HG, manufactured by Asahi Carbon Co., Ltd.]and 200.0 parts by weight of heavy calcium carbonate [trade name:Whitone SB manufactured by Shiraishi Calcium Kaisha, Ltd.] were addedthereto and kneaded for 4 minutes, and the resulting compound wasdischarged. The temperature of the compound after discharge was 150 to170° C. The kneading was carried out in a Banbury mixer having a volumeof 16 L (manufactured by Kobe Steel, Ltd.) in a charging degree of 70%.

Then, this compound was wound on 14-inch open rolls (the surfacetemperature of a former roll, 50° C.; the surface temperature of alatter roll, 50° C.; number of revolutions of the former roll, 16 rpm;the number of revolutions of the latter roll, 18 rpm), and 2.0 parts ofa vulcanizing agent sulfur, 2.0 parts of 2-mercaptobenzothiazole (MBT)[trade name: Sunseller MBT manufactured by Sanshin Chemical IndustryCo., Ltd.], 0.8 part by weight of zinc dibutyldithiocarbamate (ZnBDC)[trade name: Sunseller ZnBDC manufactured by Sanshin Chemical IndustryCo., Ltd.], 0.8 part by weight of zinc dimethyldithiocarbamate (ZnMDC)[trade name: Sunseller ZnMDC manufactured by Sanshin Chemical IndustryCo., Ltd.] and 2.0 parts by weight of N,N′-diethylthiourea (DEU) [tradename: Sunseller DEU manufactured by Sanshin Chemical Industry Co., Ltd.]as vulcanizing accelerators, 7.0 parts by weight of azodicarbonamide[trade name: Vinyhole AC#LQ manufactured by Eiwa Kasei Kogyo] as afoaming agent, and 7.0 parts by weight of an urea-based foamingassistant [trade name: Cell Paste 101W, manufactured by Eiwa ChemicalInd. Co., Ltd.] were added thereto and dispersed and kneaded for 6minutes, and the kneaded product was gaged into a ribbon of 10 mm inthickness and 70 mm in width to give a non-vulcanized non-foamed rubbercomposition.

As shown in FIG. 2, the rubber composition thus obtained was introducedinto a φ60 mm rubber extruder 2, and then the extruded non-vulcanizednon-foamed rubber composition 3 was passed through a spraying device 4and passed continuously through a molding line wherein a vulcanizingbath 7 (180° C., 4 kW) and a heated air vulcanizing bath (HAV) 8 (240°C., 5 minutes) were connected in series in an ultra-high frequencyvulcanizing device (UHF), to give a tubular vulcanized rubber foamedproduct having an outer diameter of 30 mm and an inner diameter of 24mm.

The rate of the conveyor belt was regulated such that the extruder 2 wasat a rate of 2.5 m/min., the UHF 7 outlet was 2.7 m/min., the HAV 8outlet was 2.9 m/min., and a take-off unit (not shown) was 3.2 m/min.

The treatment liquid (1) 6 was sprayed by the spraying device 4 onto thesurface of the non-vulcanized non-foamed rubber composition 3 until thenon-vulcanized non-foamed rubber composition 3 reached the UHFvulcanizing bath 7. In the spray method, a compressor was combined witha pressure-sending tank, and a spraying gun (HM-3: nozzle diameter 1.0mm) 5 manufactured by Fuso Seiki Co., Ltd. was used.

According to the methods described above, the vulcanized rubber foamedproduct thus obtained was measured for the surface roughness of theproduct, the surface roughness of the internal surface of the hollow,tensile strength at break (T_(B)), tensile elongation at break (E_(B)),compression set (CS), specific gravity, improvement of foamingefficiency, and the amount of sulfur present in the surface and theinside of the product.

The results are shown in Table 3.

Comparative Example 5

A tubular vulcanized rubber foamed product having an outer diameter of30 mm and an inner diameter of 24 mm was prepared in the same manner asin Example 7 except that the surface treatment with the treatment liquid(1) was not conducted.

According to the methods described above, the vulcanized rubber foamedproduct thus obtained was measured for the surface roughness of theproduct, the surface roughness of the internal surface of the hollow,tensile strength at break (T_(B)), tensile elongation at break (E_(B)),compression set (CS), specific gravity, improvement of foamingefficiency, and the amount of sulfur present in the surface and theinside of the product.

The results are shown in Table 3. TABLE 3 Comparative Example 7 Example5 Treatment liquid (1) Not treated Method of applying the treatmentliquid Spray system Surface roughness(μm) Surface of the product 5 14Internal surface of the hollow in the 16 17 product Mechanical strengthproperties TB (MPa) 0.8 0.5 EB (%) 180 120 Compression set (%) 18 23Evaluation of abrasion resistance 3 1 Evaluation Specific gravity 0.030.09 Improvement of foaming efficiency (%) 66 0 Amount of present sulfur(atom-%) Surface of the product 0.6 0.2 Inside of the product 0.3 0.3Ratio of present sulfur 2.0 0.7

From Table 3, the following can be understood.

In the ultra-low-specific-gravity sponge product prepared in Example 7by using the surface treatment method of the present invention, theratio of present sulfur is 2.0, and the surface smoothness is improved,and the improvement of foaming efficiency is extremely high. In theultra-low-specific-gravity sponge product prepared in ComparativeExample 5 without using the surface treatment method of the presentinvention, on the other hand, the ratio of present sulfur is 0.7, andthe product is poor in surface smoothness.

Example 8

[Preparation of Non-Vulcanized Non-Foamed Rubber Composition andVulcanized Rubber Foamed Product]

First, 120.0 parts by weight of ethylene/propylene/non-conjugatedpolyene copolymer rubber (EPT-A) were masticated for 30 seconds, andthen 5.0 parts by weight of zinc oxide, 2.0 parts by weight of stearicacid and 50.0 parts by weight of a softening agent [trade name:Dianaprocess PW-380, paraffin oil manufactured by Idemitsu Kosan Co.,Ltd.] were added thereto and finally 100.0 parts by weight of SRF carbonblack [trade name: Asahi #50HG, manufactured by Asahi Carbon Co., Ltd.]and 30.0 parts by weight of heavy calcium carbonate [trade name: WhitoneSB manufactured by Shiraishi Calcium Kaisha, Ltd.] were added theretoand kneaded for 4 minutes, and the resulting compound was discharged.The temperature of the compound after discharge was 150 to 170° C. Thekneading was carried out in a Banbury mixer having a volume of 16 L(manufactured by Kobe Steel, Ltd.) in a charging degree of 70%.

Then, this compound was wound on 14-inch open rolls (the surfacetemperature of a former roll, 50° C.; the surface temperature of alatter roll, 50° C.; number of revolutions of the former roll, 16 rpm;the number of revolutions of the latter roll, 18 rpm), and 0.7 part of avulcanizing agent sulfur, 2.0 parts of 2-mercaptobenzothiazole (MBT)[trade name: Sunseller MBT manufactured by Sanshin Chemical IndustryCo., Ltd.]., 0.8 part by weight of zinc dibutyldithiocarbamate (ZnBDC)[trade name: Sunseller ZnBDC manufactured by Sanshin Chemical IndustryCo., Ltd.] and 0.8 part by weight of zinc diethyldithiocarbamate (ZnEDC)[trade name: Sunseller ZnEDC manufactured by Sanshin Chemical IndustryCo., Ltd.] as vulcanizing accelerators, 10.0 parts by weight ofN,N′-dinitrosopentamethylene tetramine (DPT) [trade name: Celler Dmanufactured by Eiwa Chemical Ind. Co., Ltd.] as a foaming agent and11.0 parts by weight of a foaming assistant [trade name: Cell Paste K5manufactured by Eiwa Chemical Ind. Co., Ltd.] were added thereto anddispersed and kneaded for 6 minutes, and the kneaded product was gagedinto a ribbon of 0.10 mm in thickness and 70 mm in width to give anon-vulcanized non-foamed rubber composition.

As shown in FIG. 2, the rubber composition thus obtained was introducedinto a φ60 mm, rubber extruder 2, and then the extruded non-vulcanizednon-foamed rubber composition 3 was passed through a spraying device 4and passed continuously through a molding line wherein a vulcanizingbath 7 (180° C., 4 kW) and a heated air vulcanizing bath (HAV) 8 (240°C., 5 minutes) were connected in series in an ultra-high frequencyvulcanizing device (UHF), to give a tubular vulcanized rubber foamedproduct having an outer diameter of 30 mm and an inner diameter of 20mm.

The rate of the conveyor belt was regulated such that the extruder 2 wasat a rate of 2.5 m/min., the UHF 7 outlet was 2.7 m/min., the HAV 8outlet was 2.9 m/min., and a take-off unit (not shown) was 3.2 m/min.

The treatment liquid (1) 6 was sprayed by the spraying device 4 onto thesurface of the non-vulcanized non-foamed rubber composition 3 until thenon-vulcanized non-foamed rubber composition 3 reached the UHFvulcanizing bath 7. In the spraying method, a compressor was combinedwith a pressure-sending tank, and a spraying gun (HM-3: nozzle diameter1.0 mm) 5 manufactured by Fuso Seiki Co., Ltd. was used.

According to the methods described above, the vulcanized rubber foamedproduct thus obtained was measured for the surface roughness of theproduct, the surface roughness of the internal surface of the hollow,tensile strength at break (T_(B)), tensile elongation at break (E_(B)),compression set (CS), specific gravity, improvement of foamingefficiency, and the amount of sulfur present in the surface and theinside of the product.

The results are shown in Table 4.

Comparative Example 6

A tubular vulcanized rubber foamed product having an outer diameter of28 mm and an inner diameter of 20 mm was prepared in the same manner asin Example 8 except that the surface treatment with the treatment liquid(1) was not conducted.

According to the methods described above, the vulcanized rubber foamedproduct thus obtained was measured for the surface roughness of theproduct, the surface roughness of the internal surface of the hollow,tensile strength at break (T_(B)), tensile elongation at break (E_(B)),compression set (CS), specific gravity, improvement of foamingefficiency, and the amount of sulfur present in the surface and theinside of the product.

The results are shown in Table 4. TABLE 4 Comparative Example 8 Example6 Treatment liquid (1) Not treated Method of applying the treatmentliquid Spray system Surface roughness (μm) Surface of the product 5 14Internal surface of the hollow in the 15 15 product Mechanical strengthproperties TB(MPa) 1.6 0.9 EB(%) 280 220 Compression set (%) 45 55Evaluation of abrasion resistance 3 1 Evaluation Specific gravity 0.190.32 Improvement of foaming efficiency (%) 41 0 Amount of present sulfur(atom-%) Surface of the product 0.6 0.2 Inside of the product 0.3 0.3Ratio of present sulfur 2.0 0.7

From Table 4, the following can be understood.

In the thermally insulating sponge product prepared in Example 8 byusing the surface treatment method of the present invention, the ratioof present sulfur is 2.0, and the surface smoothness is improved, andthe improvement of foaming efficiency is extremely high. In thethermally insulating sponge product prepared in Comparative Example 6without using the surface treatment method of the present invention, onthe other hand, the ratio of present sulfur is 0.7, and the product ispoor in surface smoothness.

Example 9

[Preparation of Non-Vulcanized Rubber Composition and Vulcanized RubberFoamed Product]

First, 110.0 parts by weight of ethylene/propylene/non-conjugatedpolyene copolymer rubber (EPT-B) were masticated for 30 seconds, andthen 5.0 parts by weight of zinc oxide, 1.0 part by weight of stearicacid and 55.0 parts by weight of a softening agent [trade name:Dianaprocess PW-380, paraffin oil manufactured by Idemitsu Kosan Co.,Ltd.] were added thereto, and finally 170.0 parts by weight of FEFcarbon black [trade name: Asahi #60G, manufactured by Asahi Carbon Co.,Ltd.] and 15.0 parts by weight of heavy calcium carbonate [trade name:Whitone SB manufactured by Shiraishi Calcium Kaisha, Ltd.] were addedthereto and kneaded for 4 minutes, and the resulting compound wasdischarged. The temperature of the compound after discharge was 150 to170° C. The kneading was carried out in a Banbury mixer having a volumeof 16 L (manufactured by Kobe Steel, Ltd.) in a charging degree of 70%.

Then, this compound was wound on 14-inch open rolls (the surfacetemperature of a former roll, 50° C.; the surface temperature of alatter roll, 50° C.; number of revolutions of the former roll, 16 rpm;the number of revolutions of the latter roll, 18 rpm), and 0.8 part of avulcanizing agent sulfur, 1.0 part of2-(4′-morpholinodithio)benzothiazole (MDB) [trade name: Nocseller MDMmanufactured by Ouchishinko Chemical Industrial Co., Ltd.], 0.4 part byweight of tetrabutyl thiuram disulfide (TBTD) [trade name: SunsellerTBTD manufactured by Sanshin Chemical Industry Co., Ltd.], 0.4 part byweight of zinc dibutyldithiocarbamate (ZnBDC) [trade name: SunsellerZnBDC manufactured by Sanshin Chemical Industry Co., Ltd.] and 0.4, partby weight of 2-mercapto-2-imidazoline (EU) [trade name: Sunseller Eumanufactured by Sanshin Chemical Industry Co., Ltd.] as vulcanizingaccelerators, and 5.0 parts by weight of a hygroscopic agent [tradename: Besta #BS manufactured by Inoue Sekkai Kogyo Co., Ltd.] were addedthereto and dispersed and kneaded for 6 minutes, and the kneaded productwas gaged into a ribbon of 10 mm in thickness and 70 mm in width to givea non-vulcanized rubber composition.

As shown in FIG. 2, the rubber composition thus obtained was introducedinto a φ60 mm rubber extruder 2, and then the extruded non-vulcanizedrubber composition 3 was passed through a spraying device 4 and passedcontinuously through a molding line wherein a vulcanizing bath 7 (180°C., 4 kW) and a heated air vulcanizing bath (HAV) 8 (240° C., 5 minutes)were connected in series in an ultra-high frequency vulcanizing device(UHF) to give a tubular vulcanized rubber product (hose) having an outerdiameter of 15 mm and an inner diameter of 13 mm.

The rate of the conveyor belt was regulated such that the extruder 2 wasat a rate of 2.5 m/min., the UHF 7 outlet was 2.7 m/min., the HAV 8outlet was 2.9 m/min., and a take-off unit (not shown) was 3.2 m/min.

The treatment liquid (1) 6 was sprayed by the spraying device 4 onto thesurface of the non-vulcanized rubber composition 3 until thenon-vulcanized rubber composition 3 reached the UHF vulcanizing bath 7.In the spray method, a compressor was combined with a pressure-sendingtank, and a spraying gun (HM-3: nozzle diameter 1.0 mm) 5 manufacturedby Fuso Seiki Co., Ltd. was used.

According to the methods described above, the vulcanized rubber productthus obtained was measured for the surface roughness of the product,compression set (CS), specific gravity, and the amount of sulfur presentin the surface and the inside of the product.

The results are shown in Table 5.

Comparative Example 7

A tubular vulcanized rubber product (hose) having an outer diameter of15 mm and an inner diameter of 13 mm was prepared in the same manner asin Example 9 except that the surface treatment with the treatment liquid(1) was not conducted.

According to the methods described above, the vulcanized rubber productthus obtained was measured for the surface roughness of the product,compression set (CS), specific gravity, and the amount of sulfur presentin the surface and the inside of the product.

The results are shown in Table 5.

Comparative Example 8

A tubular vulcanized rubber product (hose) having an outer diameter of15 mm and an inner diameter of 13 mm was obtained in the same manner asin Example 9 except that in preparing the non-vulcanized rubbercomposition, the amount of sulfur blended was 0.96 part by weight, theamounts of vulcanizing accelerators MDB, TBTD, ZnBDC and EU blended were1.2 parts by weight, 0.48 part by weight, 0.48 part by weight and 0.48parts by weight respectively, and also that the surface treatment withthe treatment liquid (1) was not conducted.

According to the methods described above, the vulcanized rubber productthus obtained was measured for the surface roughness of the product, thesurface roughness of the internal surface of the hollow, compression set(CS), specific gravity, and the amount of sulfur present in the surfaceand the inside of the product.

The results are shown in Table 5. TABLE 5 Comparative ComparativeExample 9 Example 7 Example 8 Treatment liquid (1) Not treated Nottreated Method of applying the Spray system treatment liquid Surfaceroughness (μm) Surface of the product 3 8 6 Internal surface of the 6 66 hollow in the product Mechanical strength properties TB (MPa) 13.512.1 11.5 EB (%) 350 320 280 Compression set (%) 30 34 32 Evaluation ofabrasion 3 2 2 resistance Evaluation Specific gravity 1.24 1.24 1.24Amount of present sulfur (atom-%) Surface of the product 0.6 0.2 0.2Inside of the product 0.2 0.2 0.2 Ratio of present sulfur 3.0 1.0 1.0

From Table 5, the following can be understood.

The glass run channel product in Example 9 is a solid extruded moldedproduct, and is thus superior in surface smoothness to a sponge product.In Example 9, the surface treatment method of the present invention isused thereby improving surface smoothness, mechanical strength andelongation (mechanical strength properties). This is understood bycomparison with Comparative Example 8.

Generally, as the degree of crosslinkage is increased (as the amount ofthe vulcanizing agent is increased), abrasion resistance is improved. InComparative Example 8, therefore, the vulcanizing agent and thevulcanizing accelerators were blended respectively in amounts which were1.2-times as high as those in Example 9 to achieve similar abrasionresistance, but the resulting glass run channel product was poor inmechanical strength and elongation. Accordingly, it can be understoodthat surface smoothness, mechanical strength properties and abrasionresistance cannot be simultaneously improved by compounding thevulcanizing agent etc.

Example 10

[Preparation of Rubber Composition and Vulcanized Rubber Product]

First, 15.0 parts by weight of ethylene/propylene/non-conjugated polyenecopolymer rubber (EPT-D) and 93.0 parts by weight ofethylene/propylene/non-conjugated polyene copolymer rubber (EPT-B) weremasticated for 30 seconds, and then 3.0 parts by weight of active zincwhite [trade name: METAZ-102 manufactured by Inoue Sekkai Kogyo], 1.0part by weight of stearic acid and 113.0 parts by weight of paraffin oil[trade name: Dianaprocess PA-90 manufactured by Idemitsu Kosan Co.,Ltd.] were added thereto, and finally 170.0 parts by weight of FEFcarbon black [trade name: Asahi #60G, manufactured by Asahi Carbon Co.,Ltd.] were added thereto and kneaded for 4 minutes, and the resultingcompound was discharged. The temperature of the compound after dischargewas 150 to 170° C. The kneading was carried out in a Banbury mixerhaving a volume of 16 L (manufactured by Kobe Steel, Ltd.) in a chargingdegree of 70%.

Then, this compound was wound on 14-inch open rolls (the surfacetemperature of a former roll, 50° C.; the surface temperature of alatter roll, 50° C.; number of revolutions of the former roll, 16 rpm;the number of revolutions of the latter roll, 18 rpm), and 1.5 parts byweight of Sunfel R [trade mane, manufactured by Mitsui Chemicals, Inc.]and 0.4 part by weight of sulfur as vulcanizing agents, 0.7 part ofN-cyclohexyl-2-benzothiazolyl sulfenamide (CBS) [trade name: SunsellerCBS manufactured by Sanshin Kagaku Kogyo], 1.5 parts by weight of zincdibutyldithiocarbamate (ZnBDC) [trade name: Sunseller ZnBDC manufacturedby Sanshin Chemical Industry Co., Ltd.], 0.5 part by weight oftetramethyl thiuram disulfide (TMTD) [trade name: Sunseller TTmanufactured by Sanshin Chemical Industry Co., Ltd.], 0.5 part by weightof dipentamethylene thiuram tetrasulfide (DPTT) [trade name: SunsellerDPTT manufactured by Sanshin Chemical Industry Co., Ltd.] and 0.25 partby weight of tellurium diethyl dithiocarbamate (TeEDC) [trade name:Sunseller TTTE manufactured by Sanshin Chemical Industry Co., Ltd.] asvulcanizing accelerators were added thereto and dispersed and kneadedfor 6 minutes, and the kneaded product was gaged into a ribbon of 10 mmin thickness and 70 mm in width to give a non-vulcanized rubbercomposition.

As shown in FIG. 2, the non-vulcanized rubber composition thus obtainedwas introduced into a φ60 mm rubber extruder 2, and then the extrudednon-vulcanized rubber composition 3 was passed through a spraying device4 and passed continuously through a molding line wherein a vulcanizingbath 7 (180° C., 4 kW) and a heated air vulcanizing bath (HAV) 8 (240°C., 5 minutes) were connected in series in an ultra-high frequencyvulcanizing device (UHF), to give a tubular vulcanized rubber product(hose product) having an outer diameter of 10 mm and an inner diameterof 8 mm.

The rate of the conveyor belt was regulated such that the extruder 2 wasat a rate of 2.5 m/min., the UHF 7 outlet was 2.7 m/min., the HAV 8outlet was 2.9 m/min., and a take-off unit (not shown) was 3.2 m/min.

The treatment liquid (1) 6 was sprayed by the spraying device 4 onto thesurface of the non-vulcanized rubber composition 3 until thenon-vulcanized rubber composition 3 reached the UHF vulcanizing bath 7.In the spraying method, a compressor was combined with apressure-sending tank, and a spraying gun (HM-3: nozzle diameter 1.0 mm)5 manufactured by Fuso Seiki Co., Ltd. was used.

According to the methods described above, the vulcanized rubber productthus obtained was measured for the surface roughness of the product, thesurface roughness of the internal surface of the hollow, compression set(CS), specific gravity and the amount of sulfur present in the surfaceand the inside of the product.

The results are shown in Table 6.

Comparative Example 9

A tubular vulcanized rubber product (hose product) having an outerdiameter of 10 mm and an inner diameter of 8 mm was prepared in the samemanner as in Example 10 except that the surface treatment with thetreatment liquid (1) was not conducted.

According to the methods described above, the vulcanized rubber productthus obtained was measured for the surface roughness of the product, thesurface roughness of the internal surface of the hollow, compression set(CS), specific gravity and the amount of sulfur present in the surfaceand the inside of the product.

The results are shown in Table 6. TABLE 6 Comparative Example 10 Example9 Treatment liquid (1) Not treated Method of applying the Spray systemtreatment liquid Surface roughness (μm) Surface of the product 3 9Internal surface of the 9 9 hollow in the product Mechanical strengthproperties TB (MPa) 13.4 11.9 EB (%) 320 270 Compression set (%) 36 42Evaluation of abrasion 3 2 resistance Evaluation Specific gravity 1.211.21 Amount of present sulfur (atom-%) Surface of the product 0.5 0.2Inside of the product 0.2 0.2 Ratio of present sulfur 2.5 1.0

The hose product obtained in Example 10 is produced by using the surfacetreatment method of the present invention, in preparation of the hoseproduct, and the ratio of present sulfur is 2.5-times, the surfacesmoothness, mechanical strength and elongation of the product areimproved, and the abrasion resistance is also improved.

Example 11

As shown in FIG. 4, the rubber composition obtained in Example 1 wasintroduced into a φ60 mm rubber extruder 12, and then the shapednon-vulcanized non-foamed rubber composition 13 was passed through aspraying device 21 described later and passed continuously through amolding line wherein a vulcanizing bath 17 (180° C., 4 kW) and a heatedair vulcanizing bath (HAV) 18 (240° C., 5 minutes) were connected inseries in an ultra-high frequency vulcanizing device (UHF), whereby thetubular non-vulcanized rubber having an inner diameter of 10 mm and anouter diameter of 11 mm (thickness 1 mm), extruded through a die of therubber extruder, was vulcanized and foamed to give sponge rubber. Therate of the conveyor belt was regulated such that the extruder 12 was ata rate of 2.5 m/min., the UHF 17 outlet was 2.7 m/min., the HAV 18outlet was 2.9 m/min., and a take-off unit (not shown) was 3.2 m/min.

A treatment liquid (4) prepared in a manner described later was sprayedby the spraying device 21 described later onto the surface of the shapednon-vulcanized non-foamed rubber composition 13 until the non-vulcanizednon-foamed rubber composition 13 reached the UHF vulcanizing bath 17.

[Preparation of Treatment Liquid (4)]

A500-ml four-necked flask equipped with a nitrogen inlet, a thermometerand a propeller stirrer was placed on a water bath, and nitrogen wasintroduced into the flask, and 262.5 g purified water and 6 g nonionicsurfactant polyoxyethylene lauryl ether as a dispersant were introducedinto the flask in a nitrogen atmosphere, and the mixture was stirredwith the stirrer to dissolve a dispersant.

When the dispersant was dissolved, 30 g colloidal sulfur (capable ofpassing through a 300-mesh screen) and 1.5 g of 10 wt % aqueous solutionof polyvinyl alcohol (completely saponified, a polymerization degree of1700) as a stabilizer were added to the flask.

While the temperature in the flask was kept at 30° C. or less, themixture was stirred continuously for 5 hours, and the colloidal sulfurwas dispersed sufficiently to give liquid (4).

[Spraying Device 21]

In FIG. 4, the spraying device 21 includes a spray booth 14 equippedwith a plurality of nozzles 15 for spraying a spray liquid and a spraytank 16, and the spraying device 21 and spray booth 14 are formed with ahole through which the shaped non-vulcanized rubber composition 13 ispassed.

The nozzle 15 is a siphon two-fluid nozzle through which a spray liquidis suctioned by an air stream from the spray tank 16, to spray finedroplets of the spray liquid.

A plurality of nozzles 15 for spraying a spray liquid are arranged suchthat the nozzles are apart from one another to achieve uniform sprayingonto the whole surface of the shaped non-vulcanized rubber composition13.

Specifically, a plurality of nozzles 15 are arranged such that they areapart from one another at a certain angle around the axis in the longerdirection of the shaped non-vulcanized rubber composition 13, so as topermit the spray nozzles to be always directed towards the shapednon-vulcanized rubber 13. Depending on the shape of the shapednon-vulcanized rubber, Composition 13, the spray liquid can thereby besprayed at various angles, and even if the shaped non-vulcanized rubbercomposition 13 has a complicated lip, the whole of the lip can besprayed so that the whole surface of the shaped non-vulcanized rubbercomposition 13 can be uniformly sprayed.

Although the means of arranging nozzles 15 is not shown in the figure, aplurality of nozzles were arranged so as to be apart from one another ata predetermined angle around a hole arranged in the center of adisk-shaped nozzle bracket via a fixing device in the nozzle bracket,that is, around the axis in the longer direction of the shapednon-vulcanized rubber composition passing through the hole. In thisexample, specifically, two nozzles are arranged so as to be apart fromeach other at an angle of 180°.

The spray diameter of the above nozzle 15 is usually in the range of0.05 to 1 mm, preferably 0.1 to 0.5 mm, and the average particlediameter of spray particles form the nozzle 15 is usually in the rangeof 1 to 100 μm, preferably 10 to 50 μm. The spray liquid sprayed fromthe nozzle 15 can thereby be formed into fine spray, and the wholesurface of the shaped non-crosslinked rubber composition 13 can besprayed without deformation of the non-vulcanized rubber molded product.

The average particle diameter of spray particles from the nozzle can bemeasured by a laser diffraction particle size distribution measuringinstrument (Master Sizer 2000 manufactured by Sysmex Corporation).

In this example, specifically, a siphon 2-fluid nozzle having a sprayopening of 0.4 mm was used.

The spray liquid is placed in the spray tank 16, and the spray tank 16is provided with a stirrer to prevent precipitation.

In the spraying device 21, a means of preventing droplets adhering byspraying to the wall surface from dipping on the shaped non-vulcanizedrubber composition 13 is arranged in the spray booth 14. Specifically,the spraying device 21 is constituted such that the ceiling of the spraybooth 14 is inclined so that the adhering spray liquid runs along theinclined ceiling of the spray both 14. When molding, spraying andvulcanizing treatment are carried out plural times as a series oftreatments, droplets of the spray liquid adhering to the wall surface ofthe spray booth 14 runs along the inclined ceiling of the spray booth 14and can be recovered in a drain (not shown), whereby droplets of thespray liquid adhering to the wall surface are collected and preventedfrom dipping on the shaped non-vulcanized rubber composition 13.

Although not shown in FIG. 4, a decompression device for decompressingthe spray booth 14 to prevent leakage of droplets of the spray liquidsprayed from the spray booth 14 is arranged in the spray booth 14.

The air pressure of air stream in the nozzle was regulated at 0.26Kgf/cm², and the surface of the shaped non-vulcanized rubber composition13 was sprayed with the spray liquid.

According to the methods described above, the vulcanized rubber foamedproduct (weather strip sponge) obtained in the manner described abovewas measured for the surface roughness of the product, the surfaceroughness of the internal surface of the hollow, shape retention,tensile strength at break (T_(B)) elongation (E_(B)), compression set(CS), abrasion resistance, specific gravity, improvement of foamingefficiency, water absorptivity, and the amount of sulfur present in thesurface and the inside of the product. The results are shown in Table 7.TABLE 7 Example 11 Treatment liquid (4) Method of applying the treatmentliquid Spray system Surface roughness (μm) Surface of the product 5Internal surface of the hollow in the 22 product Shape retention (%) 86Mechanical strength properties TB (MPa) 3.9 EB (%) 300 Compression set(%) 13 Evaluation of abrasion resistance 3 Evaluation Specific gravity0.41 Improvement of foaming efficiency (%) 15 Water adsorptivity (%) 0.5Amount of present sulfur (atom-%) Surface of the product 0.7 Inside ofthe product 0.3 Ratio of present sulfur 2.3

1. A vulcanized rubber molded product wherein the amount of sulfur atomspresent in the surface of the vulcanized rubber molded product is atleast 1.2 times as high as the amount of sulfur atoms present in a cutface obtained by cutting the surface to a depth of 1.0 mm in thevertical direction.
 2. The vulcanized rubber molded product according toclaim 1, wherein the vulcanized rubber molded product is a foamedproduct.
 3. The vulcanized rubber molded product according to claim 1,wherein the vulcanized rubber molded product has a hollow part at leastpartially, and meets the following relationship:A/B<1.0 wherein A is the surface roughness (RzD) of the vulcanizedrubber molded product, and B is the roughness (RzD) of the internalsurface of the hollow.
 4. A method of producing a vulcanized rubbermolded product, which comprises allowing droplets or spray of a liquidcontaining an elementary substance consisting of a non-oxygen element inthe group VI in the periodic table to adhere to the surface of anon-vulcanized rubber composition containing an elemental sulfur and/ora sulfur compound as a crosslinking agent, and then vulcanizing orvulcanizing and foaming the composition.
 5. The method of producing avulcanized rubber molded product according to claim 4, wherein thenon-vulcanized rubber composition is shaped into a predetermined productshape, and the droplets or spray are allowed to adhere to the surface ofthe composition.
 6. The method of producing a vulcanized rubber moldedproduct according to claim 4, wherein the rubber contained in thenon-vulcanized rubber composition is ethylene/α-olefin/non-conjugatedpolyene copolymer rubber.
 7. The method of producing a vulcanized rubbermolded product according to claim 4, wherein the non-vulcanized rubbercomposition comprises a foaming agent.
 8. The method of producing avulcanized rubber molded product according to claim 4, wherein theliquid is sprayed to generate droplets or spray and allowed to adhere tothe surface of the non-vulcanized rubber composition.
 9. The method ofproducing a vulcanized rubber molded product according to claim 4,wherein the liquid is a dispersion of an elementary substance consistingof a non-oxygen element in the group VI in the periodic table. 10.(canceled)
 11. An automobile weather strip comprising the vulcanizedrubber molded product of claim
 1. 12. An automobile weather stripcomprising the vulcanized rubber molded product of claim
 2. 13. Anautomobile weather strip comprising the vulcanized rubber molded productof claim
 3. 14. An automobile glass run channel comprising thevulcanized rubber molded product of claim
 1. 15. An automobile glass runchannel comprising the vulcanized rubber molded product of claim
 2. 16.An automobile glass run channel comprising the vulcanized rubber moldedproduct of claim
 3. 17. An automobile opening trim comprising thevulcanized rubber molded product of claim
 1. 18. An automobile openingtrim comprising the vulcanized rubber molded product of claim
 2. 19. Anautomobile opening trim comprising the vulcanized rubber molded productof claim
 3. 20. An automobile hose comprising the vulcanized rubbermolded product of claim
 1. 21. An automobile hose comprising thevulcanized rubber molded product of claim
 2. 22. An automobile hosecomprising the vulcanized rubber molded product of claim 3.